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Document And Entity Information	9 Months Ended
Document And Entity Information	Sep. 30, 2019
Document Information [Line Items]
Entity Registrant Name	PROTEON THERAPEUTICS INC
Entity Central Index Key	0001359931
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Small Business	true
Document Type	S-4
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Entity Ex Transition Period	false

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 19,371,000	$ 21,170,000
Available-for-sale investments	2,496,000	20,971,000
Prepaid expenses and other current assets	1,369,000	1,339,000
Total current assets	23,236,000	43,480,000
Property and equipment, net	263,000	259,000
Restricted cash	22,000	22,000
Other non-current assets		218,000
Total assets	23,521,000	43,979,000
Current liabilities:
Accounts payable	441,000	291,000
Accrued expenses	2,637,000	8,949,000
Total current liabilities	3,078,000	9,240,000
Total liabilities	3,078,000	9,240,000
Commitments and contingencies (Note 5)
Stockholders' equity:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2019 and December 31, 2018: Series A convertible preferred stock 22,000 shares authorized at September 30, 2019 and December 31, 2018; 21,660 and 22,000 issued and outstanding at September 30, 2019 and at December 31, 2018, respectively
Common stock, $0.001 par value, 100,000,000 shares authorized at September 30, 2019 and December 31, 2018; 19,585,394 and 19,243,651 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	19,000	18,000
Additional paid-in capital	209,366,000	202,953,000
Accumulated deficit	(210,470,000)	(189,741,000)
Accumulated other comprehensive income	5,000	(14,000)
Total stockholders’ equity	20,443,000	34,739,000
Total liabilities and stockholders’ equity	23,521,000	43,979,000
Series A Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2019 and December 31, 2018: Series A convertible preferred stock 22,000 shares authorized at September 30, 2019 and December 31, 2018; 21,660 and 22,000 issued and outstanding at September 30, 2019 and at December 31, 2018, respectively	$ 21,523,000	$ 21,523,000

Consolidated Balance Sheets (Parentheticals) - $ / shares	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 02, 2017
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	19,585,394	19,243,651	17,674,729
Common stock, shares outstanding (in shares)	19,585,394	19,243,651	17,674,729
Series A Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)		$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	22,000	22,000	22,000
Preferred stock, shares issued (in shares)	21,660	22,000	22,000
Preferred stock, shares outstanding (in shares)	21,660	22,000	22,000

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating expenses:
Research and development	$ 11,848	$ 21,686	$ 18,869
General and administrative	9,524	8,676	9,836
Total operating expenses	21,372	30,362	28,705
Loss from operations	(21,372)	(30,362)	(28,705)
Other income:
Investment income	436	259	193
Other income (expense), net	207	139	(14)
Total other income	643	398	179
Net loss	(20,729)	(29,964)	(28,526)
Foreign currency translation adjustment	(1)	6
Unrealized gain on available-for-sale investments	20	(20)	11
Comprehensive loss	(20,710)	(29,978)	(28,515)
Reconciliation of net loss to net loss attributable to common stockholders:
Net loss	(20,729)	(29,964)	(28,526)
Accretion of convertible preferred stock to redemption value		(6,747)
Net loss attributable to common stockholders	$ (20,729)	$ (36,711)	$ (28,526)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (1.15)	$ (2.13)	$ (1.72)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders - basic and diluted (in shares)	18,102,219	17,274,326	16,561,799
Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:
Allocated share-based compensation	$ 3,429	$ 3,227	$ 3,343
Research and Development Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:
Allocated share-based compensation	1,142	1,109	1,114
General and Administrative Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:
Allocated share-based compensation	$ 2,287	$ 2,118	$ 2,229

Statements of Stockholders' Equity - USD ($) $ in Thousands	Series A Preferred Stock [Member] Preferred Stock [Member]	Series A Preferred Stock [Member] Additional Paid-in Capital [Member]	Series A Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2015				16,501,500
Balance at Dec. 31, 2015				$ 16	$ 194,651	$ (131,251)	$ (11)	$ 63,405
us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised				97,521
Exercise of common stock options				$ 1	196			197
Issuance of common stock upon ESPP purchase (in shares)				4,538
Issuance of common stock upon ESPP purchase					11			11
Stock-based compensation expense					3,343			3,343
Unrealized gain on available-for-sale investments							11	11
Net loss						(28,526)		(28,526)
Balance (in shares) at Dec. 31, 2016				16,603,559
Balance at Dec. 31, 2016				$ 17	198,201	(159,777)		38,441
us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised				74,001
Exercise of common stock options					108			108
Issuance of common stock upon ESPP purchase (in shares)				100,358
Issuance of common stock upon ESPP purchase					130			130
Stock-based compensation expense					3,227			3,227
Unrealized gain on available-for-sale investments								(20)
Net loss						(29,964)		(29,964)
Issuance of common stock, net of issuance costs (in shares)	22,000			896,811
Issuance of common stock, net of issuance costs	$ 14,776	$ 6,747	$ 21,523	$ 1	1,287			1,288
Accretion of Series A Convertible Preferred Stock	$ 6,747				(6,747)
Other comprehensive gain/(loss)							(14)	(14)
Balance (in shares) at Dec. 31, 2017	22,000			17,674,729
Balance at Dec. 31, 2017	$ 21,523			$ 18	202,953	(189,741)	(14)	34,739
Issuance of common stock upon ESPP purchase
Stock-based compensation expense					821			821
Net loss						(6,081)		(6,081)
Other comprehensive gain/(loss)							10	10
Balance (in shares) at Mar. 31, 2018	22,000			17,674,729
Balance at Mar. 31, 2018	$ 21,523			$ 18	203,774	(195,822)	(4)	29,489
Balance (in shares) at Dec. 31, 2017	22,000			17,674,729
Balance at Dec. 31, 2017	$ 21,523			$ 18	202,953	(189,741)	(14)	34,739
Unrealized gain on available-for-sale investments								19
Net loss								(15,470)
Balance (in shares) at Sep. 30, 2018	22,000			19,221,292
Balance at Sep. 30, 2018	$ 21,523			$ 19	208,536	(205,211)	4	24,871
Balance (in shares) at Dec. 31, 2017	22,000			17,674,729
Balance at Dec. 31, 2017	$ 21,523			$ 18	202,953	(189,741)	(14)	34,739
Issuance of common stock upon ESPP purchase (in shares)				74,343
Issuance of common stock upon ESPP purchase					132			132
Stock-based compensation expense					3,429			3,429
Unrealized gain on available-for-sale investments								20
Net loss						(20,729)		(20,729)
Issuance of common stock, net of issuance costs (in shares)				1,494,579
Issuance of common stock, net of issuance costs				$ 1	2,852			2,853
Other comprehensive gain/(loss)							19	19
Balance (in shares) at Dec. 31, 2018	22,000			19,243,651
Balance at Dec. 31, 2018	$ 21,523			$ 19	209,366	(210,470)	5	20,443
Balance (in shares) at Mar. 31, 2018	22,000			17,674,729
Balance at Mar. 31, 2018	$ 21,523			$ 18	203,774	(195,822)	(4)	29,489
Issuance of common stock upon ESPP purchase (in shares)				51,984
Issuance of common stock upon ESPP purchase					84			84
Stock-based compensation expense					922			922
Net loss						(4,879)		(4,879)
Other comprehensive gain/(loss)							5	5
Balance (in shares) at Jun. 30, 2018	22,000			17,726,713
Balance at Jun. 30, 2018	$ 21,523			$ 18	204,780	(200,701)	1	25,621
Issuance of common stock upon ESPP purchase (in shares)
Issuance of common stock upon ESPP purchase
Stock-based compensation expense					904			904
Unrealized gain on available-for-sale investments								3
Net loss						(4,510)		(4,510)
Issuance of common stock, net of issuance costs (in shares)				1,494,579
Issuance of common stock, net of issuance costs				$ 1	2,852			2,853
Other comprehensive gain/(loss)							3	3
Balance (in shares) at Sep. 30, 2018	22,000			19,221,292
Balance at Sep. 30, 2018	$ 21,523			$ 19	208,536	(205,211)	4	24,871
Balance (in shares) at Dec. 31, 2018	22,000			19,243,651
Balance at Dec. 31, 2018	$ 21,523			$ 19	209,366	(210,470)	5	20,443
Stock-based compensation expense					780			780
Net loss						(6,531)		(6,531)
Other comprehensive gain/(loss)							(2)	(2)
Balance (in shares) at Mar. 31, 2019	21,660			19,585,394
Balance at Mar. 31, 2019	$ 21,183			$ 19	210,486	(217,001)	3	14,690
Balance (in shares) at Dec. 31, 2018	22,000			19,243,651
Balance at Dec. 31, 2018	$ 21,523			$ 19	209,366	(210,470)	5	$ 20,443
us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Unrealized gain on available-for-sale investments
Net loss								(13,382)
Balance (in shares) at Sep. 30, 2019	21,660			19,585,394
Balance at Sep. 30, 2019	$ 21,183			$ 19	210,683	(223,852)	2	8,035
Balance (in shares) at Mar. 31, 2019	21,660			19,585,394
Balance at Mar. 31, 2019	$ 21,183			$ 19	210,486	(217,001)	3	14,690
Stock-based compensation expense					101			101
Net loss						(5,315)		(5,315)
Other comprehensive gain/(loss)							1	1
Balance (in shares) at Jun. 30, 2019	21,660			19,585,394
Balance at Jun. 30, 2019	$ 21,183			$ 19	210,587	(222,316)	4	9,477
Stock-based compensation expense					96			96
Unrealized gain on available-for-sale investments
Net loss						(1,536)		(1,536)
Other comprehensive gain/(loss)							(2)	(2)
Balance (in shares) at Sep. 30, 2019	21,660			19,585,394
Balance at Sep. 30, 2019	$ 21,183			$ 19	$ 210,683	$ (223,852)	$ 2	$ 8,035

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net loss	$ (20,729,000)	$ (29,964,000)	$ (28,526,000)
Reconciliation of net loss to net cash used in operating activities:
Depreciation	115,000	148,000	123,000
Amortization of premium/discount on available-for-sale securities	(51,000)	(2,000)	131,000
Unrealized loss on forward foreign currency contracts included in net income			(127,000)
Foreign currency remeasurement (loss)/gain	(25,000)	(173,000)	76,000
Stock-based compensation	3,429,000	3,227,000	3,343,000
Changes in:
Prepaid expenses and other assets	141,000	297,000	246,000
Interest receivable	49,000	(46,000)	(26,000)
Accounts payable and accrued expenses	(6,162,000)	4,161,000	1,073,000
Net cash used in operating activities	(23,233,000)	(22,352,000)	(23,687,000)
Investing activities
Purchases of available-for-sale investments	(15,443,000)	(32,942,000)	(39,756,000)
Proceeds from maturities of available-for-sale investments	31,990,000	16,878,000	59,943,000
Proceeds from sale of available-for-sale investments	1,999,000
Purchase of property and equipment	(119,000)	(35,000)	(271,000)
Net cash provided by investing activities	18,427,000	(16,099,000)	19,916,000
Financing activities
Proceeds from issuance of common stock, net of issuance costs	2,853,000	1,288,000
Proceeds from the issuance of Series A Convertible Preferred Stock, net of issuance costs		21,523,000
Proceeds from issuance of common stock under ESPP	132,000	130,000	11,000
Exercise of stock options		108,000	197,000
Net cash provided by financing activities	2,985,000	23,049,000	208,000
Effect of exchange rate changes on cash	22,000	180,000	(76,000)
Decrease in cash, cash equivalents and restricted cash	(1,799,000)	(15,222,000)	(3,639,000)
Cash, cash equivalents and restricted cash, beginning of period	21,192,000	36,414,000	40,045,000
Cash, cash equivalents and restricted cash, end of period	19,393,000	21,192,000	36,414,000
Supplemental disclosure of non-cash investing and financing activities
Accretion of convertible preferred stock		$ 6,747,000

Note 1 - Organization and Operations

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Nature of Operations [Text Block]

Organization and Operations

The Company

Proteon Therapeutics, Inc. (the “Company”) is a biopharmaceutical company that has historically focused on the development of novel,

first

-in-class pharmaceuticals to address the medical needs of patients with kidney and vascular disease. The Company was formed in

June 2001

and incorporated on

March 24, 2006.

March 28, 2019,

the Company announced that its

second

Phase

trial, PATENCY-

for vonapanitase did

not

meet its co-primary endpoints of fistula use for hemodialysis (

p=0.328

) and secondary patency (

p=0.932

). The PATENCY-

clinical trial was the

second

two

randomized, double-blind Phase

trials, comparing a

microgram dose of investigational vonapanitase to placebo in patients with chronic kidney disease, or CKD, undergoing creation of a radiocephalic fistula for hemodialysis. Following the release of top-line data from the PATENCY-

clinical trial of vonapanitase on

March 28, 2019,

the Company began to evaluate its strategic alternatives focusing on enhancing stockholder value. It is conducting the process with the assistance of financial and legal advisors and is evaluating the full range of potential strategic alternatives, including but

not

limited to, a merger or sale of the Company, including a sale of assets or intellectual property, business combinations, joint ventures, public and private capital raises and recapitalization options. As part of these efforts, on

April 15, 2019,

the Company announced the engagement of H.C. Wainwright & Co., LLC as its financial advisor to assist in the strategic review process. Since these efforts

may

not

be successful, the Company is also considering other possible alternatives, including a wind-down of operations and a liquidation and dissolution of the Company. On

September 23, 2019,

the Company entered into a merger agreement with ArTara Therapeutics, Inc. (“ArTara”). The Company has discontinued substantially all its research and development activities, including a reduction in workforce, to reduce operating expenses while it evaluates these opportunities. As of

September 30, 2019,

the Company has terminated all but

one

of its employees. The Company has recorded severance costs of

$2.9

million, all of which was recorded in the

three

months ended

June 30, 2019.

These severance related expenses were fully recorded in the

three

months ending

June 30, 2019.

The Company remains subject to a number of risks similar to other companies in the biotechnology industry, including compliance with government regulations, protection of proprietary technology, dependence on

third

parties and product liability.

Liquidity and Going Concern

As of

September 30, 2019,

the Company had cash and cash equivalents of

$9.3

million. The Company believes that its existing cash and cash equivalents will be sufficient to fund its projected cash needs into

2020

and enable it to complete the proposed merger with ArTara, pursuant to which REM

Acquisition

Inc. (the “Merger Sub”), a wholly owned subsidiary of the Company, will be merged with and into ArTara, with ArTara surviving as a wholly owned subsidiary of the Company (the “Merger”). However, if there is a delay in completing the Merger, the Company will require additional capital to sustain its operations through such completion or the Company will need to pursue an immediate dissolution. If the Company needs additional capital, it would need to raise such capital through debt or equity financings, asset sales or other strategic transactions. However, there can be

assurances that the Company will be able to complete any such transaction on acceptable terms or otherwise. The failure to obtain sufficient funds on commercially acceptable terms when needed could have a material adverse effect on the Company’s business, results of operations and financial condition and

may

prevent it from completing the Merger. Accordingly, these factors, among others, raise substantial doubt about the Company’s ability to continue as a going concern.

The Company had an accumulated deficit of

$223.9

million as of

September 30, 2019.

The Company anticipates operating losses to continue for the foreseeable future due to, among other things, costs related to its administrative organization. Additionally, as stated above, the Company announced that its

second

Phase

trial, PATENCY-

for vonapanitase did

not

meet its co-primary endpoints. As a result, the Company has discontinued substantially all its research and development activities to reduce operating expenses while it evaluates its strategic alternatives, including the Merger.

These conditions raise substantial doubt about its ability to continue as a going concern within

one

year after the date that the financial statements are issued. To alleviate the conditions that raise substantial doubt about the Company’s ability to continue as a going concern, management has implemented a reduction in expenditures plan and as referenced above is pursuing a merger. While the current reduction in spending expenditure plans will allow the Company to fund its operations in the near-term, there can be

assurance that the Company will be able to achieve its future strategic alternatives raising substantial doubt about its ability to continue as a going concern.

Pursuant to the requirements of Accounting Standards Codification (ASC)

205

40,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within

one

year after the date that the financial statements are issued. This evaluation initially does

not

take into consideration the potential mitigating effect of management’s plans that have

not

been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (

) it is probable that the plans will be effectively implemented within

one

year after the date that the financial statements are issued, and (

) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within

one

year after the date that the financial statements are issued.

Under ASC

2015

40,

the strategic alternatives being pursued by the Company, including the Merger, cannot be considered probable at this time because

none

of the Company’s current plans have been finalized at the time of filing this Quarterly Report on Form

-Q and the implementation of any such plan is

not

probable of being effectively implemented as

none

of the plans are entirely within the Company’s control. Accordingly, substantial doubt is deemed to exist about the Company’s ability to continue as a going concern within

one

year after the date these financial statements are issued.

The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do

not

include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Merger Agreement

September 23, 2019,

the Company entered into a merger agreement (the “Merger Agreement”) with ArTara. Pursuant to the Merger Agreement, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, the Merger Sub, a wholly owned subsidiary of the Company, will merge with and into ArTara, with ArTara surviving as a wholly owned subsidiary of the Company.

Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of ArTara common stock outstanding immediately prior to the Effective Time (excluding certain shares to be canceled pursuant to the Merger Agreement and shares held by stockholders who have exercised and perfected appraisal rights will be converted into the right to receive a number of shares of the Company’s common stock equal to the exchange ratio, as more fully described below.

The Merger is intended to qualify for U.S. federal income tax purposes as a reorganization under the provisions of Section

368

(a) of the Internal Revenue Code of

1986,

as amended.

As promptly as practicable after the date of the Merger Agreement (but in

event later than

days following the date of the Merger Agreement), the parties will prepare and the Company will file with the U.S. Securities and Exchange Commission (“SEC”) a Registration Statement on Form S-

(the “Registration Statement”) to register the shares of the Company’s common stock to be issued at the Effective Time under the Securities Act, and the Company will seek the approval of its stockholders with respect to certain actions, including the following (collectively, the “Company Stockholder Matters”):

the issuance of shares of the Company’s common stock to ArTara's stockholders in connection with the transactions contemplated by the Merger Agreement and shares of the Company’s capital stock to the institutional investors in the Private Placement, pursuant to The Nasdaq Stock Market LLC (“Nasdaq”) rules;

the amendment of the Company’s certificate of incorporation (i) to effect immediately prior to the closing of the Merger a reverse split of all outstanding shares of the Company’s common stock at a reverse stock split ratio of

one

new share for every

(or any number in between) shares outstanding (the “Reverse Split”) and (ii) to effect immediately after the consummation of the Private Placement the automatic conversion of all outstanding shares of Series A Convertible Preferred Stock (the “Series A Preferred Stock”) of the Company into shares of the Company’s common stock, without given effect to any existing provision that limits the conversion rights of the Series A Preferred Stock (including, without limitation, the

9.985%

beneficial ownership cap) (the “Series A Preferred Automatic Conversion”); and

an amendment to the Company’s Amended and Restated

2014

Equity Incentive Plan (the “Plan”) to increase the shares available for issuance thereunder by such additional number of shares of the Company’s common stock such that the total number of shares of the Company’s common stock reserved for issuance under the Plan, after giving effect to such additional shares, would

not

exceed

15.2%

of the shares of the Company’s common stock outstanding immediately after the Effective Time, after giving effect to the Reverse Split, the Private Placement and the Series A Preferred Automatic Conversion, as determined by or on behalf of ArTara prior to the effectiveness of the Registration Statement (the “EIP Amendment”).

The consummation of the Merger is also subject to the satisfaction or waiver of certain conditions, including, among other things, (i) approval by the Company’s stockholders and ArTara’s stockholders (other than with respect to the EIP Amendment), (ii) Nasdaq approval of the listing of the shares to be issued to ArTara equity holders in connection with the consummation of the Merger, (iii) satisfaction of all conditions precedent to the closing of the Private Placement (other than the consummation of the Merger and appointment of certain board members), (iv) absence of a material adverse effect since the date of the Merger Agreement, (v) the accuracy of the representations and warranties, subject to material adverse effect qualifications, (vi) compliance by the parties with their respective covenants in all material respects, (vii) the Subscription Agreement (as defined below) being in full force and effect and

less than

$40.0

million to be committed thereunder and (viii) the Company having at least

in net cash as of the closing date of the Merger (the “Company Net Cash condition”).

The Merger Agreement contains certain termination rights for both the Company and ArTara, and further provides that, upon termination of the Merger Agreement under specified circumstances, the Company

may

be required to pay to ArTara a termination fee of

$0.8

million or ArTara

may

be required to pay to the Company a termination fee of

$0.8

million, and in other circumstances each party

may

be required to reimburse the other party's expenses incurred, up to a maximum of

$0.4

million.

In accordance with the terms of the Merger Agreement, (i) certain executive officers, directors and stockholders of ArTara (solely in their respective capacities as ArTara stockholders) have entered into support agreements with ArTara and the Company to vote all of their shares of ArTara capital stock in favor of adoption of the Merger Agreement and (ii) certain of the Company’s executive officers, directors and stockholders (solely in their respective capacities as the Company’s stockholders) have entered into support agreements with ArTara and the Company to vote all of their shares of the its common stock in favor of the Company’s Stockholder Matters. Concurrently with the execution of the Merger Agreement, the Company’s director and ArTara's directors and officers have entered into lock-up agreements pursuant to which they accepted certain restrictions on transfer of shares of its common stock for the

180

-day period following the closing of the Merger.

At the Effective Time, the Company will effect a name change and it is anticipated that trading for the Company’s securities will be listed on The Nasdaq Capital Market. Additionally, at the Effective Time, the Company’s board of directors is expected to consist of

seven

members, with

five

such members designated by ArTara,

one

such member designated by the Company, and

one

such member who will be Mr. Jesse Shefferman, the Chief Executive Officer of the combined company.

Private Placement

In connection with the Merger, on

September 23, 2019,

the company has entered into a Subscription Agreement (the “Subscription Agreement”) with certain institutional investors (the “Investors”), pursuant to which the Company has agreed to issue in a private placement (the “Private Placement”) (i) up to

27,200

shares of the Company’s Series

Convertible Non-Voting Preferred Stock, par value

$0.001

per share (the “Series

Preferred Stock”), at a purchase price equal to

1,000

times the Common Stock Purchase Price (as defined below) and (ii) up to

15,300

shares of the Company’s common stock (together with the Series

Preferred Stock, the “Private Placement Shares”), at a purchase price equal to (

) the Aggregate Valuation (as defined in the Merger Agreement) divided by the (y) the Post-Closing Parent Shares (as defined in the Merger Agreement) (the “Common Stock Purchase Price”).

Pursuant to the Subscription Agreement, the holders of Series

Preferred Stock have preemptive rights to participate pro rata in the Company’s future equity financings, subject to certain exceptions and limitations. In addition, following the issuance of the Private Placement Shares pursuant to the Subscription Agreement, certain of the Investors have rights to nominate directors to the Company’s board of directors and non-voting board observers. The Company has also agreed

not

to take certain actions related to the business without the consent of the lead investor for so long as such lead investor continues to hold a minimum amount of the Private Placement Shares purchased under the Subscription Agreement.

Prior to the issuance of the Private Placement Shares, the Company intends to file a Certificate of Designation of Preferences, Rights and Limitations of Series

Convertible Non-Voting Preferred Stock (the "Certificate of Designation") with the Delaware Secretary of State. Thereunder, each share of Series

Preferred Stock will be convertible into

1,000

shares of the Company’s common stock, at a conversion price initially equal to the Common Stock Purchase Price, subject to adjustment for any stock splits, stock dividends and similar events, at any time at the option of the holder, provided that any conversion of Series

Preferred Stock by a holder into shares of the Company’s common stock would be prohibited if, as a result of such conversion, the holder, together with its affiliates and any other person or entity whose beneficial ownership of the common stock would be aggregated with such holder’s for purposes of Section

(d) of the Exchange Act would beneficially own more than

9.99%

of the total number of shares of the Company’s common stock issued and outstanding after giving effect to such conversion. Upon written notice to the Company, the holder

may

from time to time increase or decrease such limitation to any other percentage

not

in excess of

19.99%

specified in such notice.

Each share of Series

Preferred Stock will be entitled to a preference of

$10.00

per share upon the Company’s liquidation, and thereafter will share ratably in any distributions or payments on an as-converted basis with the holders of the Company’s common stock. In addition, upon the occurrence of certain transactions that involve the Company’s merger or consolidation, an exchange or tender offer, a sale of all or substantially all of the Company’s assets or a reclassification of the Company’s common stock, each share of Series

Preferred Stock will be convertible into the kind and amount of securities, cash and/or other property that the holder of a number of shares of the Company’s common stock issuable upon conversion of

one

share of Series

Preferred Stock would receive in connection with such transaction.

The Private Placement is expected to close immediately following the consummation of the Merger.

Organization and Operations

The Company

Proteon Therapeutics, Inc. (the “Company”) is a late-stage biopharmaceutical company focused on the development of novel,

first

-in-class pharmaceuticals to address the medical needs of patients with kidney and vascular disease. The Company was formed in

June 2001

and incorporated on

March 24, 2006.

The Company devotes substantially all of its efforts to product research and development, initial market development and raising capital. The Company has

not

generated any product revenue related to its primary business purpose to date and is subject to a number of risks similar to those of other development stage companies, including dependence on key individuals, competition from other companies, the need for development of commercially viable products and the need to obtain adequate additional financing to fund the development of its product candidates. The Company is also subject to a number of risks similar to other companies in the biotechnology industry, including regulatory approval of products, uncertainty of market acceptance of products, competition from therapeutic alternatives and larger companies, compliance with government regulations, protection of proprietary technology, dependence on

third

parties and product liability.

Liquidity and Going Concern

As of

December 31, 2018,

the Company had cash, cash equivalents and available-for-sale investments of

$21.9

million. The Company believes that its existing cash, cash equivalents and available-for-sale investments will be sufficient to fund operations and capital expenditures into the

first

quarter of

2020.

The Company had an accumulated deficit of

$210.5

million as of

December 31, 2018.

Based on these available cash resources, the Company does

not

have sufficient cash on hand to support current operations for at least the next

twelve

months from the date of filing this Annual Report on Form

-K. This condition raises substantial doubt about the Company’s ability to continue as a going concern.

The Company’s plans to address this condition include pursuing

one

or more of the following options to secure additional funding,

none

of which can be guaranteed or are entirely within our control:

•

raise additional funding through the possible sale of additional shares of the Company’s common stock, including public or private equity financings, and/or possible debt financings; and

•

use the worldwide commercial rights to vonapanitase currently held by the Company to establish partnerships for the development and commercialization of vonapanitase in all or parts of Europe and other countries outside of the United States to secure additional funding.

There can be

assurance, however, that the Company will receive cash proceeds from any of these potential sources or to the extent cash proceeds are received those proceeds would be sufficient to support our current operating plan for at least the next

twelve

months from the date of filing this Annual Report on Form

-K.

Pursuant to the requirements of Accounting Standards Codification (ASC)

205

40,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within

one

year after the date that the financial statements are issued. This evaluation initially does

not

take into consideration the potential mitigating effect of management’s plans that have

not

) it is probable that the plans will be effectively implemented within

one

year after the date that the financial statements are issued, and (

) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within

one

year after the date that the financial statements are issued.

Under ASC

2015

40,

the future receipt of potential funding from the Company’s partners and other resources cannot be considered probable at this time because

none

of the Company’s current plans have been finalized at the time of filing this Annual Report on Form

-K and the implementation of any such plan is

not

probable of being effectively implemented as

none

of the plans are entirely within the Company’s control. Accordingly, substantial doubt is deemed to exist about the Company’s ability to continue as a going concern within

one

year after the date these financial statements are issued.

The Company believes that its approximate

$21.9

million in cash, cash equivalents and marketable securities at

December

31,

2018,

as described above, would allow it to fund its planned operations into the

first

quarter of

2020.

This estimate assumes

equity financings,

debt financings and

funding from new partnership agreements. Accordingly, the timing and nature of activities contemplated for the remainder of

2019

and thereafter will be conducted subject to the availability of sufficient financial resources.

If the Company is unable to obtain sufficient capital to continue to advance its programs, the Company would be forced to delay, reduce or eliminate its ongoing development and other activities.

not

At-The-Market Equity Offering Program

November 12, 2015,

the Company filed a shelf registration statement on Form S-

(the “Registration Statement”), and entered into a Sales Agreement with Cowen and Company, LLC (the “Sales Agreement”) to establish an at-the-market (“ATM”) equity offering program pursuant to which they are able, with the Company’s authorization, to offer and sell up to

$40

million of the Company’s Common Stock at prevailing market prices from time to time. The Registration Statement became effective on

January 12, 2016.

The Company paid Cowen a commission equal to

of the gross proceeds of the sales price of all shares sold through it as sales agent under the Sales Agreement. The offering costs were offset against proceeds from the sale of common stock under this agreement. The Company filed a prospectus supplement on

March 16, 2017

because the Company is currently subject to General Instruction

I.B.6

of Form S-

which limits the amounts that the Company

may

sell under the Registration Statement. The Company’s ATM program was terminated effective as of

February 7, 2019,

when its new shelf registration statement on Form S-

File

No.

333

228865,

was declared effective by the SEC. For the year ended

December 31, 2017,

the Company sold

896,811

shares of Common Stock under the Sales Agreement for aggregate gross proceeds of

$1.4

million offset by total offering costs of

$0.1

million. For the year ended

December 31, 2018,

the Company sold

1,494,579

shares of Common Stock under the Sales Agreement for aggregate gross proceeds of

$3.0

million. For the year ended

December 31, 2018,

total offering costs of

$46,000,

were offset against the proceeds from the sale of common stock. The

1,494,579

shares of Common Stock sold under the ATM program during the year ended

December 31, 2018

were all sold on

September 25, 2018

to New Leaf Venture Partners LLC.

Series A Preferred Financing

June 22, 2017,

the Company entered into a Securities Purchase Agreement (the “Purchase Agreement”) with a syndicate of current and new institutional investors, led by an affiliate of Deerfield Management Company, L.P., pursuant to which the Company agreed to issue and sell to the “Investors” an aggregate of

22,000

shares of the Company’s Series A Convertible Preferred Stock, par value

$0.001

per share (the “Transaction”), for a purchase price of

$1,000

per share, or an aggregate gross purchase price of

$22.0

million, all upon the terms and conditions set forth in the Purchase Agreement. The Company closed this Transaction on

August 2, 2017 (

see Note

August 2, 2017,

the Company entered into a registration rights agreement with the Investors (the “Registration Rights Agreement”). On

August 3, 2017,

in accordance with the Registration Rights Agreement, the Company filed a registration statement on Form S-

to register the common stock issuable upon conversion of the Preferred Shares. The registration statement became effective on

August 21, 2017.

Note 2 - Summary of Significant Accounting Policies

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Significant Accounting Policies [Text Block]

Summary of Significant Accounting Policies

Basis of Presentation, Principles of Consolidation and Use of Estimates

The unaudited interim condensed consolidated financial statements of the Company included herein have been prepared, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements as of and for the year ended

December 31, 2018

and notes thereto, included in the Company’s Annual Report on Form

-K, as filed with the SEC on

March 13, 2019.

The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company’s management, the accompanying unaudited interim condensed consolidated financial statements contain all adjustments which are necessary to fairly present the Company’s financial position as of

September 30, 2019,

the results of its operations for the

three

and

nine

months ended

September 30, 2019

and

2018,

results of changes in stockholders equity for the

nine

months ended

September 30, 2019

and

2018,

and its cash flows for the

nine

months ended

September 30, 2019

and

2018.

Such adjustments are of a normal and recurring nature. The results for the

three

and

nine

months ended

September 30, 2019

are

not

necessarily indicative of the results for the year ending

December 31, 2019,

or for any future period.

The unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates, which include, but are

not

limited to, estimates related to stock-based compensation expense, clinical trial accruals and reported amounts of revenues and expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results

may

differ from those estimates or assumptions.

Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, available-for-sale investments, accounts payable, and accrued liabilities. The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC Topic

820,

Fair Value Measurement and Disclosures

, established a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the financial instrument based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the financial instrument and are developed based on the best information available under the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported or disclosed fair value of the financial instruments and is

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents and available-for-sale investments. There have been

changes to the valuation methods utilized by the Company during the

three

and

nine

months ended

September 30, 2019

and

2018.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the

three

and

nine

months ended

September 30, 2019

and

2018.

Net Income (Loss) per Share Attributable to Common Stockholders

Basic net income (loss) per share is calculated by dividing net income (loss) attributable to common stockholders by the weighted-average number of common shares outstanding during the period. Diluted net income per share is calculated by dividing the net income attributable to common stockholders by the weighted-average number of common equivalent shares outstanding for the period, including any dilutive effect from outstanding stock options and warrants using the treasury stock method.

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The

two

-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders when participating securities are outstanding, losses are

not

allocated to the participating securities. For purposes of calculating diluted net income per share attributable to common stockholders, preferred stock, stock options, warrants and convertible debt are considered common stock equivalents.

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers (“ASU

2014

09”

), a new standard on revenue recognition providing a single, comprehensive revenue recognition model for all contracts with customers. The new revenue standard is based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new standard was effective beginning

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

), which increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. At the lease commencement date, the lessee must recognize a lease liability and right-of-use asset, which is initially measured at the present value of future lease payments. The Company adopted ASU

2016

January 1, 2019

using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and will

not

restate prior periods. It has have also elected to adopt the package of practical expedients permitted in Accounting Standards Codification Topic

842,

or ASC

842.

Accordingly, it is continuing to account for its existing operating lease as an operating lease under the new guidance, without reassessing whether the contract contains a lease under ASC

842

or whether classification of the operating leases would be different under ASC Topic

842,

and to treat lease and non-lease components as a single lease component. The Company’s sole lease at the adoption date was an operating lease for facilities and did

not

include any non-lease components.

As a result of the adoption of ASU

2016

02,

January 1, 2019,

the Company recognized (a) a lease liability of approximately

$0.2

million, which represents the present value of its remaining lease payments using an estimated incremental borrowing rate of

8%,

(b) a right-of-use asset of approximately

$0.2

million that will be expensed as operating lease expense over the term of the lease. Due to the adoption of the standard using the retrospective cumulative-effect adjustment method, there are

changes to previously reported results prior to

January 1, 2019.

Lease expense is

not

expected to change materially as a result of the adoption of ASU

2016

02.

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments (“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

Statement of Cash Flows, Restricted Cash requiring restricted cash and restricted cash equivalents to be included with cash and cash equivalents on the statement of cash flows when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The guidance is effective for interim and annual periods beginning after

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

Restricted cash is now included as a component of cash, cash equivalents, and restricted cash on the Company’s unaudited condensed consolidated statement of cash flows. Restricted cash is recorded within other non-current assets in the accompanying unaudited condensed consolidated balance sheets. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and the ending balances by

$22,000

for both the

nine

months ended

September 30, 2019

and

2018.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting (“ASU

2017

09”

), which clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. The new guidance will reduce diversity in practice and result in fewer changes to the terms of an award being accounted for as modifications. Under ASU

2017

09,

an entity will

not

apply modification accounting to a share-based payment award if the award’s fair value, vesting conditions and classification as an equity or liability instrument are the same immediately before and after the change. ASU

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

aims to simplify the accounting for share-based payments to nonemployees by aligning it to the accounting for share based payments to employees including determining the fair value of the award on the date of grant and recognizing the stock-based compensation expense as of the respective vesting date. The new standard also requires companies to elect to either measure the awards to nonemployees over an estimated expected term or contractual term as well as elect to estimate forfeitures or account for forfeitures as incurred. ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company adopted ASU

2018

during the quarter ended

March 31, 2019.

The adoption did

not

have an impact on the condensed consolidated financial statements as all outstanding non-employee share-based awards had vested prior to

March 31, 2018.

Summary of Significant Accounting Policies

Basis of Presentation, Principles of Consolidation and Use of Estimates

The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

not

limited to, estimates related to stock-based compensation expense, clinical trial accruals and reported amounts of expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results

may

differ from those estimates or assumptions.

Segment Information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company and the Company's chief operating decision maker view the Company's operations and manage its business in

one

operating segment, which is the business of developing and commercializing vonapanitase for the treatment of renal and vascular disease. Currently, the Company operates in only

one

geographic segment.

Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, available-for-sale investments, forward foreign currency contracts (see Note

), accounts payable, and accrued liabilities. The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC Topic

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents, available-for-sale investments and forward foreign currency contracts (see Note

). There have been

changes to the valuation methods utilized by the Company during the years ended

December 31, 2018

and

2017.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the years ended

December 31, 2018

and

2017.

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers

(“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

January 1, 2019

and expects to elect certain practical expedients permitted under the transition guidance. Additionally, we will elect the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and will

not

restate prior periods. The Company is substantially complete in assessing the transitional impact from adopting the standard. The Company currently estimates that the adoption of the new lease standard will have an immaterial impact on the consolidated financial statements.

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments

(“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

Statement of Cash Flows, Restricted Cash

requiring restricted cash and restricted cash equivalents to be included with cash and cash equivalents on the statement of cash flows when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The guidance is effective for interim and annual periods beginning after

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and

$14,000

for the years ended

December 31, 2018

and

2017,

respectively. The ending balances were increased by

$22,000

for both the years ended

December 31, 2018

and

2017.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting

(“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company is currently evaluating the impact of the new guidance on its condensed consolidated financial statements.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of

days or less from the purchase date to be cash equivalents. Cash and cash equivalents are held in depository and money market accounts and are reported at fair value.

Short-Term Investments

The Company classifies its investments as available-for-sale and records such assets at estimated fair value in the consolidated balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the consolidated statements of operations and comprehensive loss and as a separate component of stockholders' equity (deficit). The Company invests its excess cash balances primarily in government debt securities and money market funds with strong credit ratings and maturities of less than

one

year. There have been

realized gains and losses for the years ended

December 31, 2018,

2017

and

2016.

At each balance sheet date, the Company assesses available-for-sale securities in an unrealized loss position to determine whether the unrealized loss is other-than-temporary. The Company considers factors including: the significance of the decline in value compared to the cost basis, underlying factors contributing to a decline in the prices of securities in a single asset class, the length of time the market value of the security has been less than its cost basis, the security's relative performance versus its peers, sector or asset class, expected market volatility and the market and economy in general. When the Company determines that a decline in the fair value below its cost basis is other-than-temporary, the Company recognizes an impairment loss in the year in which the other-than-temporary decline occurred. There have been

other-than-temporary declines in value of short-term investments for the years ended

December 31, 2018,

2017

and

2016,

as it is more likely than

not

the Company will hold the securities until maturity or a recovery of the cost basis.

Concentrations of Credit Risk and Off-Balance Sheet Risk

Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash, cash equivalents and short-term investments. The Company's cash and cash equivalents are held in accounts with financial institutions that management believes are creditworthy. The Company's investment policy includes guidelines on the quality of the institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentration of credit risk. These amounts at times

may

exceed federally insured limits. The Company has

not

experienced any credit losses in such accounts and does

not

believe it is exposed to any significant credit risk on these funds. The Company has

financial instruments with off-balance sheet risk of loss.

Property and Equipment

Property and equipment is stated at cost, less accumulated depreciation. Maintenance and repairs that do

not

improve or extend the lives of the respective assets are expensed to operations as incurred. When capitalizing assets for research and development purposes the Company evaluates whether an alternative future use of the asset exists; if

not,

such assets are expensed as research and development. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation is recorded using the straight-line method over the estimated useful lives of the respective assets, which are as follows:

Asset	Estimated Useful Life (in years)
Computer equipment and software		3
Furniture, fixtures and other		5
Laboratory equipment		7

Research and Development Costs

Research and development costs are charged to expense as incurred in performing research and development activities. The costs include employee compensation costs, facilities and overhead, clinical study and related clinical manufacturing costs, regulatory and other related costs. Nonrefundable advanced payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed.

Stock-Based Compensation Expense

The Company accounts for its stock-based compensation awards to employees and directors in accordance with FASB ASC Topic

718,

Compensation-Stock Compensation

(“ASC

718”

). ASC

718

requires all stock-based payments to employees, including grants of employee stock options and restricted stock, to be recognized in the consolidated statements of operations and comprehensive loss based on their grant date fair values. Compensation expense related to awards to employees is recognized on a straight-line basis based on the grant date fair value over the associated service period of the award, which is generally the vesting term. Share-based payments issued to non-employees are recorded at their fair values and are periodically revalued as the equity instruments vest and are recognized as expense over the related service period in accordance with the provisions of ASC

718

and FASB ASC Topic

505,

Equity

and are expensed using an accelerated attribution model.

The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate, (d) expected dividends and (e) the estimated fair value of its Common Stock on the measurement date. Due to the lack of company specific historical and implied volatility data of its Common Stock, the Company has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. When selecting these public companies on which it has based its expected stock price volatility, the Company selected companies with comparable characteristics to it, including enterprise value, risk profiles, position within the industry and with historical share price information sufficient to meet the expected term of the stock based awards. The Company computes historical volatility data using the daily closing prices for the selected companies' shares during the equivalent period of the calculated expected term of the stock-based awards. During

2018

the Company began to estimate volatility by using a blend of our stock price history, for the length of time we have market data for our stock and the historical volatility of similar public companies for the expected term of each grant. The Company accounts for forfeitures as they occur. Due to the lack of Company specific historical option activity, the Company has estimated the expected term of its employee stock options using the “simplified” method, whereby, the expected term equals the arithmetic average of the vesting term and the original contractual term of the option. The expected term for non-employee awards is the remaining contractual term of the option. The risk-free interest rates are based on the U.S. Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid and does

not

expect to pay dividends in the foreseeable future. Refer to Note

“

Use of Estimates

,” for a discussion of the Company's estimated fair value of its Common Stock.

Income Taxes

Income taxes are recorded in accordance with FASB ASC Topic

740,

“Income Taxes” (“ASC

740”

), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and tax reporting basis of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Valuation allowances are provided if based upon the weight of available evidence, it is more likely than

not

that some or all of the deferred tax assets will

not

be realized. The Company has evaluated available evidence and concluded that the Company

may

not

realize the benefit of its deferred tax assets; therefore, a valuation allowance has been established for the full amount of the deferred tax assets.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC

740.

When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than

not

be realized. The determination as to whether the tax benefit will more likely than

not

be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of

December 31, 2018

and

2017,

the Company did

not

have any significant uncertain tax positions. The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. See Note

for further details.

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

allocated to the participating securities. For purposes of calculating diluted net income per share attributable to common shareholders, preferred stock, stock options, warrants and convertible debt are considered common stock equivalents.

Comprehensive Loss

Comprehensive loss consists of net income or loss and changes in equity during a period from transactions and other events and circumstances generated from non-owner sources. The Company's net loss equals comprehensive loss, net of any changes in the unrealized gains and losses of the Company's short-term investments, held as available-for-sale, and foreign currency translation for all periods presented.

Subsequent Events

The Company considers events or transactions that occur after the balance sheet date but prior to the date the consolidated financial statements are available to be issued for potential recognition or disclosure in the financial statements. The Company has completed an evaluation of all subsequent events after the consolidated balance sheet date of

December 31, 2018

to ensure that this filing includes appropriate disclosure of events both recognized in the consolidated financial statements as of

December 31, 2018

and events which occurred subsequently but were

not

recognized in the consolidated financial statements.

Note 3 - Fair Value Measurements

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Fair Value Disclosures [Text Block]

Fair Value Measurements

Below is a summary of assets and liabilities measured at fair value (in thousands):

	As of September 30, 2019
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	9,101	$	-	$	-	$	9,101
Total	$	9,101	$	-	$	-	$	9,101

	As of December 31, 2018
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

As of

September 30, 2019

and

December 31, 2018,

the Company’s cash equivalents consist principally of money market funds and government debt securities with original maturities of

days or less. Government securities consist principally of government debt securities and money market funds which are classified as available-for-sale.

Available-for-sale securities at

September 30, 2019

and

December 31, 2018

consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
September 30, 2019
Government securities
(Due within 1 year)	$	-	$	-	$	-	$	-
	$	-	$	-	$	-	$	-

December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-	$	2,496
	$	2,496	$	-	$	-	$	2,496

Fair Value Measurements

Below is a summary of assets and liabilities measured at fair value (in thousands):

	As of December 31, 2018
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2017
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	11,662	$	-	$	-	$	11,662
Government securities		20,971		-		-		20,971
Total	$	32,633	$	-	$	-	$	32,633

As of

December 31, 2018,

and

2017,

the Company’s cash equivalents consist principally of money market funds and government debt securities with original maturities of

days or less. Government securities consist principally of government debt securities and money market funds which are classified as available-for-sale.

Available-for-sale securities at

December 31, 2018

and

2017

consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-		$	2,496
	$	2,496	$	-	$	-		$	2,496

December 31, 2017
Government securities
(Due within 1 year)	$	20,991	$	-	$	(20	)	$	20,971
	$	20,991	$	-	$	(20	)	$	20,971

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Note 4 - Property and Equipment, Net

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	As of
	September 30, 2019		December 31, 2018

Computer equipment and software	$	-	$	211
Furniture, fixtures, and other		-		365
Laboratory equipment		-		514
		-		1,090
Accumulated depreciation		-		(827	)
Property and equipment, net	$	-	$	263

Depreciation expense for the

three

and

nine

months ended

September 30, 2019

was

$0.1

million, and

$0.3

million, respectively. Depreciation expense for the

three

and

nine

months ended

September 30, 2018

was

$22,000,

and

$0.1

million, respectively.

During the

three

months ended

March 31, 2019,

the Company voluntarily discontinued substantially all research and development activities. As a result, as of

March 31, 2019

the Company performed an impairment assessment of the laboratory equipment used in development of vonapanitase by comparing the equipment’s carrying value to its estimated fair value, which was determined based on the recoverability of the assets remaining value as of

March 31, 2019.

As of

September 30, 2019,

the Company performed an additional impairment assessment due to the expiration of their lease agreement. The fair value of the remaining assets including office furniture, computer hardware and software licenses were determined be impaired as the Company determined there to be

future use for the assets. The Company recorded an impairment charges of

zero

and

$0.2

million during the

three

and

nine

months ended

September 30, 2019.

As of

September 30, 2019,

property and equipment balance remained as a result of the impairment.

Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	As of December 31,
	2018			2017

Computer equipment and software	$	211		$	192
Furniture, fixtures, and other		365			302
Laboratory equipment		514			477
		1,090			971
Accumulated depreciation		(827	)		(712	)
Property and equipment, net	$	263		$	259

Depreciation expense for the years ended

December 31, 2018,

2017

and

2016

was

$0.1

million,

$0.1

million, and

$0.1

million, respectively.

Note 5 - Accrued Expenses

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Accounts Payable and Accrued Liabilities Disclosure [Text Block]

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	As of December 31,
	2018		2017

Payroll and employee-related costs	$	1,390	$	1,318
Contracted service costs		968		7,218
Professional fees and other		279		413
Total	$	2,637	$	8,949

Note 6 - Commitments and Contingencies

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

Commitments and Contingencies

Operating Lease

The Company’s facility is located in Waltham, Massachusetts. In

July 2018,

it amended the lease extending its expiration to

September 2019.

During the

three

and

nine

months ended

September 30, 2019,

it recognized operating lease expense of

$0.1

million and

$0.2

million, respectively including property taxes and routine maintenance expense, which approximated its cash payments for the period. The lease expired as of

September 30, 2019,

and therefore the condensed consolidated balance sheet does

not

include an operating lease right-of-use asset or an operating lease liability in other assets and other current liabilities, respectively. As of

September 30, 2019,

there are

future minimum payments required under the operating lease. As of

September 30, 2019,

the Company has provided a security deposit in the amount of

$22,000

to the lessor. The security deposit will be returned within

days of the expiration of the lease which occurred on

September 30, 2019.

Restricted cash related to facilities leases

As of

September 30, 2019

and

December 31, 2018,

the Company had

$22,000

in an outstanding letter of credit to be used as collateral for leased premises. As of

September 30, 2019

and

December 31, 2018,

the Company pledged an aggregate of

$22,000

to the bank as collateral for the letter of credit, which is included in other current assets and non-current assets, respectively. The security deposit will be returned within

days of the expiration of the lease which occurred on

September 30, 2019.

Commitments and Contingencies

Significant Contracts and Agreements

February 2002,

the Company entered into an agreement to license certain intellectual property with Johns Hopkins University. The agreement calls for payments to be made by the Company upon the commencement of product sales, in the form of a royalty of

2.5%

on net sales of the product. As of

December 31, 2018

the Company has

not

commenced product sales and therefore has recognized

royalties on product sales.

Operating Leases

The Company has various non-cancellable operating leases for facilities and office equipment that expire at various dates through

2019.

August 2017,

the Company entered into an Amendment (the “Lease Amendment”) to the existing Lease Agreement dated

July 13, 2009 (

the “Lease Agreement”), with Boston Properties Limited Partnership (“Lessor”) pursuant to which the Company has agreed to (i) extend the term of the lease for a period of

fifteen

(

) months from

June 30, 2018

until

September 30, 2019

and (ii) increase the Company’s office space under the Lease Agreement by

2,552

square feet of additional property for a total of approximately

7,500

square feet of property (the “Leased Property”). The Leased Property is located at

200

West St., Waltham, Massachusetts. In addition, the Company has the option to extend the term of the Lease Agreement for an additional

one

-year period upon the Company’s written notice to the Lessor at least

six

months prior to the expiration of the term. Rental expense was

$0.3

million,

$0.2

million and

$0.2

million for the years ended

December 31, 2018,

2017

and

2016,

respectively.

Future minimum payments required under operating leases as of

December 31, 2018

are summarized as follows (in thousands):

Year Ending December 31:	Amount

2019		207
Total minimum lease payments	$	207

In addition to the base rent, the Company is also responsible for its share of operating expenses and real estate taxes, in accordance with the terms of the lease agreement. As of

December 31, 2018,

the Company has provided a security deposit in the amount of

$22,000

to the lessor.

Restricted cash related to facilities leases

December 31, 2018

and

2017,

the Company had

$22,000

respectively, in an outstanding letter of credit to be used as collateral for leased premises. At

December 31, 2018

and

2017,

the Company pledged an aggregate of

$22,000

to the bank as collateral for the letter of credit, which is included in other non-current assets.

Note 7 - Series A Preferred Financing

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Preferred Stock [Text Block]

Series A Preferred Financing

August 2, 2017,

the Company issued and sold

22,000

shares of the Company’s Series A Convertible Preferred Stock, par value of

$0.001

per share (the “Series A Preferred”), for a purchase price of

$1,000

per share, or aggregate purchase price and gross proceeds of

$22.0

million, all upon the terms and conditions set forth in the Securities Purchase Agreement dated as of

June 22, 2017.

The Company incurred

$0.5

million of issuance costs in connection with the transaction. Each share of Series A Preferred is convertible into approximately

1,005

shares of the Company’s Common Stock at a conversion price of

$0.9949

per share, in each case subject to adjustment for any stock splits, stock dividends and similar events, provided that any conversion of Series A Preferred by a holder into shares of Common Stock is prohibited if, as a result of such conversion, the holder, together with its affiliates and any other person or entity whose beneficial ownership of the Company’s Common Stock would be aggregated with such holder’s for purposes of Section

(d) of the Exchange Act would beneficially own more than

9.985%

of the total number of shares of Common Stock issued and outstanding after giving effect to such conversion. At

December 31, 2018

and

2017,

the Company had

22,000

shares of Series A Convertible Preferred Stock authorized.

Upon issuance, each share of Series A Preferred included an embedded beneficial conversion feature as the market price of the Company’s Common Stock on the date of issuance of the Series A Preferred was

$1.30

per share. As a result, the Company recorded the intrinsic value of the beneficial conversion feature of

$6.7

million as a discount on the Series A Preferred at issuance. As the Series A Preferred is immediately convertible upon issuance and does

not

include a stated redemption date, the discount on the Series A Preferred was immediately accreted.

The Company evaluated the Series A Preferred for liability or equity classification in accordance with the provisions of ASC

480,

Distinguishing Liabilities from Equity, and determined that equity treatment was appropriate because the Series A Preferred did

not

meet the definition of the liability instruments defined thereunder for convertible instruments. Specifically, the Series A Preferred are

not

mandatorily redeemable and do

not

embody an obligation to buy back the shares outside of the Company’s control in a manner that could require the transfer of assets. Additionally, the Company determined that the Series A Preferred would be recorded as permanent equity,

not

temporary equity, based on the guidance of ASC

480

given that there is

scenario where the holders of equally and more subordinated equity of the entity would

not

be entitled to also receive the same form of consideration upon the occurrence of the event that gives rise to the redemption.

Dividends

Holders of the Series A Preferred Stock are entitled to receive dividends, if and when declared by the Board of Directors.

Liquidation Preference

Holders of the Series A Preferred Stock have preference in the event of a liquidation or dissolution of the Company equal to

$0.001

per share, plus any declared dividends.

Thereafter, the Holders of the shares of Series A Preferred Stock shall share ratably in any distributions and payments of any remaining assets of the Company, on an as converted basis, with the holders of Common Stock.

Voting Rights

Except for matters with specific voting rights as provided in the Series A Preferred Stock Purchase Agreement, the Holders of shares of Series A Preferred Stock have

voting rights.

Note 8 - Common Stock

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Common Stock [Text Block]

Common Stock

General

December 31, 2018,

the Company has

100,000,000

shares of Common Stock authorized for issuance,

$0.001

par value per share, of which

19,243,651

shares were issued and outstanding.

Reserved for Future Issuance

The Company has the following shares of Common Stock reserved for future issuance:

	December 31,		December 31,
	2018		2017

Conversion of Series A Preferred Stock		22,112,775		22,112,775
Stock-based compensation awards		5,163,957		3,572,457
Employee Stock Purchase Plan		118,120		192,463
Total		27,394,852		25,877,695

Note 9 - Stock-based Compensation

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Share-based Payment Arrangement [Text Block]

Stock-based Compensation

Stock Options

The following table summarizes stock option activity for employees:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Granted		1,182,500		$	2.66
Exercised		-
Forfeited (1)		(2,606,289	)	$	2.79
Expired (1)		(2,400,590	)	$	6.51
Outstanding at September 30, 2019		772,847		$	4.89		7.3	$	-
Exercisable at September 30, 2019		476,390		$	6.13		6.4	$	-
Vested or expected to vest at September 30, 2019 (2)		772,847		$	4.89		7.3	$	-

_____________________

(

) Represents the number of options cancelled during the

nine

months ended

September 30, 2019

as a result of employees that were terminated due to the reduction in force.

(

) Represents the number of vested options at

September 30, 2019

plus the number of unvested options expected to vest based on the unvested options outstanding at

September 30, 2019.

Employee Stock Purchase Plan

The

2014

Employee Stock Purchase Plan (ESPP) initially authorized the issuance of up to

140,500

shares of Common Stock. The number of shares increases each

January 1,

commencing on

January 1, 2015

and ending on (and including)

January 1, 2024,

by an amount equal to the lesser of

one

percent of the outstanding shares as of the end of the immediately preceding fiscal year,

281,000

shares and any lower amount determined by the Company’s Board of Directors prior to each such

January

1st.

As of

September 30, 2019,

as a result of an increase on

January 1, 2019

one

percent of the outstanding shares as of the end of the fiscal year ending

December 31, 2018,

the

2014

ESPP authorized the issuance of up to

192,436

shares of Common Stock. The

tenth

offering under the

2014

ESPP began on

July 1, 2019

and ended on

September 30, 2019.

shares were issued during the

three

and

nine

months ended

September 30, 2019.

shares and

51,984

shares were issued during the

three

and

nine

months ended

September 30, 2018

under the

2014

ESPP. The Company incurred

zero

and

$68,000

in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2019

respectively. The Company incurred

$20,000

and

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2018,

respectively.

Common Stock

The Company has the following shares of Common Stock reserved for future issuance:

	September 30,		December 31,
	2019		2018

Conversion of Series A Preferred Stock		21,771,032		22,112,775
Stock-based compensation awards		6,818,214		5,163,957
Employee Stock Purchase Plan		118,120		118,120
Total		28,707,366		27,394,852

Stock-based Compensation

August 21, 2014,

the Company’s Board of Directors superseded the

2006

Equity Incentive Plan (the

“2006

Plan”) with the

2014

Equity Incentive Plan (the

“2014

Plan”), and the

2014

Employee Stock Purchase Plan (the

“2014

ESPP”). On

October 3, 2014,

the stockholders approved these plans. The stockholders also approved an amendment to the

2014

Plan on

July 31, 2017.

The Plans provide for the grant of incentive and non-statutory stock options, stock appreciation rights, restricted stock and stock unit awards, performance units, stock grants and qualified performance-based awards. Under the

2006

Plan,

new stock compensation awards will be granted subsequent to the completion of the Company’s IPO. The Company initially reserved

704,000

shares of Common Stock for issuance under the

2014

Plan. The

2014

Plan provides that the number of shares reserved and available for issuance under the

2014

Plan will automatically increase each

January 1,

beginning

January 1, 2015

four

percent of the outstanding shares of Common Stock on the immediately preceding

December 31

or such lesser number of shares as determined by the Company’s Board of Directors prior to each such

January

1st.

Terms of the stock awards, including vesting requirements, are determined by the Board of Directors, subject to the provisions of the Plans. Options granted by the Company typically vest over

three

four

years. Certain awards provide for accelerated vesting if there is a change in control as defined in the Plans. Stock options outstanding under the

2006

Plan are exercisable from the date of grant for a period of

ten

years. Stock options granted under the

2014

Plan are exercisable only upon vesting. For options granted to date, the exercise price equaled the fair value of the Common Stock as determined by the Board of Directors on the date of grant.

Stock-based compensation expense

Total stock-based compensation expense is recognized for stock options granted to employees and non-employees and has been reported in the Company’s consolidated statements of operations as follows (in thousands):

	Year Ended December 31,
	2018		2017		2016

Research and development	$	1,142	$	1,109	$	1,114
General and administrative		2,287		2,118		2,229
Total	$	3,429	$	3,227	$	3,343

The Company estimates the fair value of each employee stock award on the grant date using the Black-Scholes option-pricing model based on the following assumptions regarding the fair value of the underlying Common Stock on each measurement date:

	Year Ended December 31,
	2018			2017			2016
Weighted average expected volatility		93.5	%		94.5	%		84.4	%
Expected term (in years)		6.07			6.06			6.05
Risk free interest rate		2.55	%		2.09	%		1.45	%
Expected dividend yield		0	%		0	%		0	%

Stock options issued to non-employees are accounted for using the fair value method of accounting; they are periodically revalued as the options vest and are recognized as expense over the related service period. The total expense related to all options granted to non-employees was

for the years ended

December 31, 2018,

2017

and

2016.

Stock Options

The following table summarizes stock option activity for employees and non-employees:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2017		2,681,072		$	7.18		6.8	$	121
Granted		2,041,600		$	2.61
Exercised		-
Forfeited		(83,433	)	$	5.82
Expired		(42,013	)	$	13.30
Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Exercisable at December 31, 2018		2,067,356		$	7.57		5.7	$	241
Vested or expected to vest at December 31, 2018 (1)		4,597,226		$	5.12		7.4	$	404

__________________

(

) Represents the number of vested options at

December 31, 2018

plus the number of unvested options expected to vest based on the unvested options outstanding at

December 31, 2018.

During the year ended

December 31, 2018,

the Company granted stock options to purchase an aggregate of

2,041,600

shares of its Common Stock with a weighted-average grant date fair value of

$2.61.

During the year ended

December 31, 2017,

the Company granted stock options to purchase an aggregate of

719,337

shares of its Common Stock with a weighted-average grant date fair value of

$1.99.

During the year ended

December 31, 2016,

the Company granted stock options to purchase an aggregate of

132,495

shares of its Common Stock with a weighted-average exercise price of

$7.11

and a weighted-average grant date fair value of

$5.08.

The total intrinsic value of options exercised in the years ended

December 31, 2018

and

2017

was

and

$27,000

respectively. As of

December 31, 2018,

and

2017

there was

$4.6

million and

$4.2

million, respectively of total unrecognized compensation cost related to employee non-vested stock options. The total unrecognized compensation cost for employee awards will be adjusted for future forfeitures. The Company expects to recognize its remaining stock-based compensation expense over a weighted-average period of

2.40

years.

Employee Stock Purchase Plan

The

2014

Employee Stock Purchase Plan (“ESPP”) initially authorized the issuance of up to

140,500

shares of Common Stock. The number of shares increases each

January 1,

commencing on

January 1, 2015

and ending on (and including)

January 1, 2024,

by an amount equal to the lesser of

one

percent of the outstanding shares as of the end of the immediately preceding fiscal year,

281,000

shares or any lower amount determined by the Company’s Board of Directors prior to each such

January

1st.

The Company’s Board of Directors determined there was to be

increase on

January 1, 2018.

As of

December 31, 2018,

the

2014

ESPP authorized the issuance of up to

304,991

shares of Common Stock. The

seventh

offering under the

2014

ESPP began on

January 1, 2018

and ended on

June 30, 2018

and the

eight

offering began on

July 1, 2018

and ended on

December 31, 2018.

During the years ended

December 31, 2018

and

2017,

74,343

and

100,358

shares, respectively, were issued under the

2014

ESPP. The Company incurred

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the years ended

December 31, 2018,

2017,

and

2016.

Note 10 - Income Taxes

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Income Tax Disclosure [Text Block]

Income Taxes

Deferred taxes are recognized for temporary differences between the basis of assets and liabilities for financial statement and income tax purposes. The Company has evaluated the positive and negative evidence bearing upon the Company’s ability to realize the benefit of its deferred tax assets. Based on the Company’s history of operating losses, the Company has concluded that it is more likely than

not

that the benefit of its deferred tax assets will

not

be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has provided a full valuation allowance against its deferred tax assets. There were

significant income tax provisions or benefits for the

nine

months ended

September 30, 2019

and

2018.

10.

Income Taxes

The components of loss from operations before income taxes are as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Domestic	$	(17,855	)	$	(24,803	)	$	(15,860	)
Foreign		(2,874	)		(5,161	)		(12,666	)
Total	$	(20,729	)	$	(29,964	)	$	(28,526	)

For the years ended

December 31, 2018,

2017,

2016,

the Company has

not

recorded a provision for federal or state income taxes as it has had net operating losses since inception.

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations is as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Income tax benefit computed at federal statutory tax rate	$	(4,348	)	$	(10,186	)	$	(9,696	)
Permanent differences		6			4			430
Stock compensation - permanent items		325			689			-
R&D credit - permanent items		-			1,751			1,437
State income taxes, net of federal benefit		(958	)		(853	)		(498	)
Tax credits		(1,466	)		(5,495	)		(4,846	)
Change in valuation allowance		5,409			(54,319	)		8,804
Foreign rate differential		602			1,752			4,304
Rate change		-			2,202			-
382 limitation		-			64,975			-
Other		430			(520	)		65
Total	$	-		$	-		$	-

The significant components of the Company's deferred tax assets are as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	6,742		$	2,651		$	37,237
Federal and state tax credits		3,122			2,244			21,223
Accrued expenses		411			399			544
Patents		132			191			360
Stock-based compensation		1,782			1,262			1,353
Other		169			202			321
Total deferred tax assets		12,358			6,949			61,038
Valuation allowance		(12,358	)		(6,949	)		(61,038	)
Net deferred assets	$	-		$	-		$	-

Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. Based on the Company's history of operating losses, management of the Company has concluded that it is more likely than

not

that the benefit of its deferred tax assets will

not

be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of

December 31, 2018,

2017,

and

2016.

December 22, 2017,

the President of the United States signed into law the Tax Cuts and Jobs Act tax reform legislation. This legislation makes significant changes in U.S. tax law including a reduction in the corporate tax rates, changes to net operating loss “NOL” carryforwards and carrybacks, and a repeal of the corporate alternative minimum tax. The legislation reduced the U.S. corporate tax rate from the current rate of

34%

21%.

As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities at the enacted rate. This revaluation resulted in a decrease in net deferred tax asset of

$2.2

million and a corresponding reduction in the valuation allowance against these assets. There is

impact to income tax expense. The other provisions of the Tax Cuts and Jobs Act did

not

have a material impact on the

2017

2018

consolidated financial statements.

The Company’s preliminary estimate of the TCJA and the remeasurement of its deferred tax assets and liabilities is subject to the finalization of management’s analysis related to certain matters, such as developing interpretations of the provisions of the TCJA, changes to certain estimates and the filing of our tax returns. U.S. Treasury regulations, administrative interpretations or court decisions interpreting the TJCA

may

require further adjustments and changes in our estimates. The Company completed the analysis of the

2017

Tax Act during the

fourth

quarter of

2018

and had

material changes to the original analysis.

Net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service (the "IRS") and

may

become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a

three

-year period in excess of

50%

as defined under Sections

382

and

383

in the Internal Revenue Code. This could substantially limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the Company's value immediately prior to the ownership change. Subsequent ownership changes

may

further affect the limitation in future years. On

August 2, 2017,

the Company completed a financing transaction for

$22.0

million. As a result of this transaction, the company performed a study to review the application of IRC

§382

and

§383

to the Company. It was determined there was an ownership change as of the date of this financing and the Company’s NOLs generated prior to

August 2, 2017

would be fully limited. Therefore, the NOLs and credits generated prior to

August 2, 2017

have been written down to zero. This represents a decrease in Federal NOLs of approximately

$107.3

million (

$34.1

million tax effected) and a decrease in federal credits of

$23.8

million. State NOLs and credits were also fully limited as a result of this ownership change. The state NOLs were reduced by approximately

$5.0

million and credits were reduced by

$2.1

million.

As a result of current year activity, the valuation allowance increased by approximately

$5.4

million during the year ended

December 31, 2018.

This was due primarily to the addition of Orphan Drug Tax credits and the generation of net operating losses. In the year ended

December 31, 2017,

the valuation allowance had an increase of approximately

$13.1

million. However, this increase was offset by a reduction of

$65.0

million due to the aforementioned

§382

limitation and a reduction of

$2.2

million due to the change in tax rate. Therefore, there was an overall decrease to the valuation allowance

$54.1

million. The valuation allowance increased by approximately

$8.8

million during the year ended

December 31, 2016,

due primarily to the addition of Orphan Drug Tax credits and the generation of net operating losses.

Subject to the limitations described below, as of

December 31, 2018,

2017,

and

2016,

the Company has net operating loss carryforwards of approximately

$25.7

million,

$10.6

million, and

$0.0

million, respectively, to offset future federal taxable income. The pre-

2018

federal net operating loss carryforwards expire at various dates through

2037.

Federal net operating loss carryforwards generated in

2018

and forward will have an unlimited carryforward period as part of the Tax Cuts and Jobs Act. The indefinite lived net operating loss carryforwards as of

December 31, 2018

are approximately

$14.7

million. As of

December 31, 2018,

2017,

and

2016,

the Company has state net operating loss carryforwards of approximately

$21.5

million,

$6.8

million, and

$0.0

million, respectively, to offset future state taxable income, which will expire at various times between

2037

and

2038.

As of

December 31, 2018,

2017

and

2016,

the Company has tax credit carryforwards of approximately

$3.1

million,

$2.3

million and

$0.0

million, respectively, to offset future federal and state income taxes, which will expire at various times between

2037

and

2038.

The Company had

unrecognized tax benefits or related interest and penalties accrued during the years ended

December 31, 2018,

2017,

and

2016.

The Company will recognize interest and penalties related to uncertain tax positions in income tax expense.

The Company is subject to U.S. federal income tax and primarily Massachusetts state income tax. The statute of limitations for assessment by the IRS and state tax authorities is open for tax years ending

December 31, 2015

through

2018,

although carryforward attributes that were generated prior to tax year

2015

may

still be adjusted upon examination by the IRS or state tax authorities if they either have been or will be used in a future period. Currently,

federal or state income tax returns are under examination by the respective taxing authorities.

Note 11 - Net Loss Per Share Attributable to Common Stockholders

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Earnings Per Share [Text Block]

Net Loss per Share Attributable to Common Stockholders

As described in Note

Summary of Significant Accounting Policies, the Company computes basic and diluted loss per share using a methodology that gives effect to the impact of outstanding participating securities (the “two-class method”). As the

three

and

nine

months ended

September 30, 2019

and

2018

resulted in net losses, there is

income allocation required under the

two

-class method or dilution attributed to weighted-average shares outstanding in the calculation of diluted loss per share.

The following Common Stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Outstanding stock options		772,847		4,597,226		772,847		4,597,226
Outstanding ESPP shares		-		26,642		-		26,642
Convertible preferred stock		21,771,032		22,112,775		21,771,032		22,112,775
		22,543,879		26,736,643		22,543,879		26,736,643

11.

Net Loss per Share Attributable to Common Stockholders

As described in Note

December 31, 2018,

2017

and

2016

resulted in net losses, there is

income allocation required under the

two

-class method or dilution attributed to weighted-average shares outstanding in the calculation of diluted loss per share. In

2017

the net loss applicable to Common Stock did

not

equal net loss due to the accretion of the beneficial conversion feature of Preferred Stock in the amount of

$6.7

million. The beneficial conversion feature was initially recorded as a discount on the Preferred Stock with a corresponding amount recorded to Additional Paid-in Capital. The discount on the preferred stock was then immediately written off as a deemed dividend as the Preferred Stock does

not

have a stated redemption date and is immediately convertible at the option of the holder.

The following Common Stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect:

	Year Ended December 31,
	2018		2017		2016
Outstanding stock options		4,597,226		2,681,072		2,166,254
Convertible preferred stock		22,112,775		22,112,775		-
		26,710,001		24,793,847		2,166,254

Note 12 - Quarterly Financial Information (Unaudited, in Thousands, Except Share and Per Share Data)

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Quarterly Financial Information [Text Block]

12.

Quarterly Financial Information (unaudited, in thousands, except share and per share data)

The following table contains selected quarterly financial information from

2018

and

2017.

The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are

not

necessarily indicative of results for any future period.

	Three Months Ended (a)
	March 31,			June 30,			September 30,			December 31,
	2018			2018			2018			2018
Operating expenses	$	6,365		$	5,000		$	4,622		$	5,385
Net loss attributable to common stockholders		(6,081	)		(4,879	)		(4,510	)		(5,259	)
Net loss per share attributable to common stockholders:
Basic and Diluted	$	(0.34	)	$	(0.28	)	$	(0.25	)	$	(0.27	)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders:
Basic and Diluted		17,674,729			17,674,729			17,824,186			19,221,292

	Three Months Ended (a)
	March 31,			June 30,			September 30,			December 31,
	2017			2017			2017			2017
Operating expenses	$	6,480		$	5,986		$	12,306		$	5,590
Net loss attributable to common stockholders		(6,498	)		(5,608	)		(19,054	)		(5,551	)
Net loss per share attributable to common stockholders:
Basic and Diluted	$	(0.39	)	$	(0.33	)	$	(1.08	)	$	(0.33	)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders:
Basic and Diluted		16,636,201			17,207,672			17,619,418	(b)		17,619,418

__________________

(a)

The amounts were computed independently for each quarter, and the sum of the quarters

may

not

total the annual amounts.

(b)

Adjusted to correct an immaterial error in the weighted-average share calculation in the Company's Form

-Q as of

September 30, 2017.

Significant Accounting Policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation, Principles of Consolidation and Use of Estimates

December 31, 2018

and notes thereto, included in the Company’s Annual Report on Form

-K, as filed with the SEC on

March 13, 2019.

September 30, 2019,

the results of its operations for the

three

and

nine

months ended

September 30, 2019

and

2018,

results of changes in stockholders equity for the

nine

months ended

September 30, 2019

and

2018,

and its cash flows for the

nine

months ended

September 30, 2019

and

2018.

Such adjustments are of a normal and recurring nature. The results for the

three

and

nine

months ended

September 30, 2019

are

not

necessarily indicative of the results for the year ending

December 31, 2019,

or for any future period.

not

may

differ from those estimates or assumptions.

Basis of Presentation, Principles of Consolidation and Use of Estimates

not

may

differ from those estimates or assumptions.

Fair Value Measurement, Policy [Policy Text Block]

Fair Value of Financial Instruments

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents and available-for-sale investments. There have been

changes to the valuation methods utilized by the Company during the

three

and

nine

months ended

September 30, 2019

and

2018.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the

three

and

nine

months ended

September 30, 2019

and

2018.

Segment Information

one

operating segment, which is the business of developing and commercializing vonapanitase for the treatment of renal and vascular disease. Currently, the Company operates in only

one

geographic segment.

Derivatives, Policy [Policy Text Block]

Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, available-for-sale investments, forward foreign currency contracts (see Note

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents, available-for-sale investments and forward foreign currency contracts (see Note

). There have been

changes to the valuation methods utilized by the Company during the years ended

December 31, 2018

and

2017.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the years ended

December 31, 2018

and

2017.

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers (“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

2016

January 1, 2019

using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and will

not

restate prior periods. It has have also elected to adopt the package of practical expedients permitted in Accounting Standards Codification Topic

842,

or ASC

842.

Accordingly, it is continuing to account for its existing operating lease as an operating lease under the new guidance, without reassessing whether the contract contains a lease under ASC

842

or whether classification of the operating leases would be different under ASC Topic

842,

and to treat lease and non-lease components as a single lease component. The Company’s sole lease at the adoption date was an operating lease for facilities and did

not

include any non-lease components.

As a result of the adoption of ASU

2016

02,

January 1, 2019,

the Company recognized (a) a lease liability of approximately

$0.2

million, which represents the present value of its remaining lease payments using an estimated incremental borrowing rate of

8%,

(b) a right-of-use asset of approximately

$0.2

million that will be expensed as operating lease expense over the term of the lease. Due to the adoption of the standard using the retrospective cumulative-effect adjustment method, there are

changes to previously reported results prior to

January 1, 2019.

Lease expense is

not

expected to change materially as a result of the adoption of ASU

2016

02.

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments (“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and the ending balances by

$22,000

for both the

nine

months ended

September 30, 2019

and

2018.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting (“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company adopted ASU

2018

during the quarter ended

March 31, 2019.

The adoption did

not

have an impact on the condensed consolidated financial statements as all outstanding non-employee share-based awards had vested prior to

March 31, 2018.

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers

(“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

January 1, 2019

not

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments

(“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

Statement of Cash Flows, Restricted Cash

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and

$14,000

for the years ended

December 31, 2018

and

2017,

respectively. The ending balances were increased by

$22,000

for both the years ended

December 31, 2018

and

2017.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting

(“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company is currently evaluating the impact of the new guidance on its condensed consolidated financial statements.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of

days or less from the purchase date to be cash equivalents. Cash and cash equivalents are held in depository and money market accounts and are reported at fair value.

Investment, Policy [Policy Text Block]

Short-Term Investments

one

year. There have been

realized gains and losses for the years ended

December 31, 2018,

2017

and

2016.

other-than-temporary declines in value of short-term investments for the years ended

December 31, 2018,

2017

and

2016,

as it is more likely than

not

the Company will hold the securities until maturity or a recovery of the cost basis.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentrations of Credit Risk and Off-Balance Sheet Risk

may

exceed federally insured limits. The Company has

not

experienced any credit losses in such accounts and does

not

believe it is exposed to any significant credit risk on these funds. The Company has

financial instruments with off-balance sheet risk of loss.

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment

Property and equipment is stated at cost, less accumulated depreciation. Maintenance and repairs that do

not

not,

Asset	Estimated Useful Life (in years)
Computer equipment and software		3
Furniture, fixtures and other		5
Laboratory equipment		7

Research and Development Expense, Policy [Policy Text Block]

Research and Development Costs

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Stock-Based Compensation Expense

The Company accounts for its stock-based compensation awards to employees and directors in accordance with FASB ASC Topic

718,

Compensation-Stock Compensation

(“ASC

718”

). ASC

718

and FASB ASC Topic

505,

Equity

and are expensed using an accelerated attribution model.

2018

not

expect to pay dividends in the foreseeable future. Refer to Note

“

Use of Estimates

,” for a discussion of the Company's estimated fair value of its Common Stock.

Income Tax, Policy [Policy Text Block]

Income Taxes

Income taxes are recorded in accordance with FASB ASC Topic

740,

“Income Taxes” (“ASC

740”

not

that some or all of the deferred tax assets will

not

be realized. The Company has evaluated available evidence and concluded that the Company

may

not

realize the benefit of its deferred tax assets; therefore, a valuation allowance has been established for the full amount of the deferred tax assets.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC

740.

When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than

not

be realized. The determination as to whether the tax benefit will more likely than

not

be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of

December 31, 2018

and

2017,

the Company did

not

have any significant uncertain tax positions. The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. See Note

for further details.

Earnings Per Share, Policy [Policy Text Block]

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

Comprehensive Income, Policy [Policy Text Block]

Comprehensive Loss

Subsequent Events, Policy [Policy Text Block]

Subsequent Events

December 31, 2018

to ensure that this filing includes appropriate disclosure of events both recognized in the consolidated financial statements as of

December 31, 2018

and events which occurred subsequently but were

not

recognized in the consolidated financial statements.

Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Property Plant and Equipment Useful Lives [Table Text Block]

Asset	Estimated Useful Life (in years)
Computer equipment and software		3
Furniture, fixtures and other		5
Laboratory equipment		7

Note 3 - Fair Value Measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	As of September 30, 2019
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	9,101	$	-	$	-	$	9,101
Total	$	9,101	$	-	$	-	$	9,101

	As of December 31, 2018
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2018
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2017
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	11,662	$	-	$	-	$	11,662
Government securities		20,971		-		-		20,971
Total	$	32,633	$	-	$	-	$	32,633

Available-for-sale Securities [Table Text Block]

	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
September 30, 2019
Government securities
(Due within 1 year)	$	-	$	-	$	-	$	-
	$	-	$	-	$	-	$	-

December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-	$	2,496
	$	2,496	$	-	$	-	$	2,496

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-		$	2,496
	$	2,496	$	-	$	-		$	2,496

December 31, 2017
Government securities
(Due within 1 year)	$	20,991	$	-	$	(20	)	$	20,971
	$	20,991	$	-	$	(20	)	$	20,971

Note 4 - Property and Equipment, Net (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Property, Plant and Equipment [Table Text Block]

	As of
	September 30, 2019		December 31, 2018

Computer equipment and software	$	-	$	211
Furniture, fixtures, and other		-		365
Laboratory equipment		-		514
		-		1,090
Accumulated depreciation		-		(827	)
Property and equipment, net	$	-	$	263

	As of December 31,
	2018			2017

Computer equipment and software	$	211		$	192
Furniture, fixtures, and other		365			302
Laboratory equipment		514			477
		1,090			971
Accumulated depreciation		(827	)		(712	)
Property and equipment, net	$	263		$	259

Note 5 - Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Accrued Liabilities [Table Text Block]

	As of December 31,
	2018		2017

Payroll and employee-related costs	$	1,390	$	1,318
Contracted service costs		968		7,218
Professional fees and other		279		413
Total	$	2,637	$	8,949

Note 6 - Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Year Ending December 31:	Amount

2019		207
Total minimum lease payments	$	207

Note 8 - Common Stock (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Common Stock Reserved for Future Issuance [Table Text Block]

	September 30,		December 31,
	2019		2018

Conversion of Series A Preferred Stock		21,771,032		22,112,775
Stock-based compensation awards		6,818,214		5,163,957
Employee Stock Purchase Plan		118,120		118,120
Total		28,707,366		27,394,852

	December 31,		December 31,
	2018		2017

Conversion of Series A Preferred Stock		22,112,775		22,112,775
Stock-based compensation awards		5,163,957		3,572,457
Employee Stock Purchase Plan		118,120		192,463
Total		27,394,852		25,877,695

Note 9 - Stock-based Compensation (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year Ended December 31,
	2018		2017		2016

Research and development	$	1,142	$	1,109	$	1,114
General and administrative		2,287		2,118		2,229
Total	$	3,429	$	3,227	$	3,343

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31,
	2018			2017			2016
Weighted average expected volatility		93.5	%		94.5	%		84.4	%
Expected term (in years)		6.07			6.06			6.05
Risk free interest rate		2.55	%		2.09	%		1.45	%
Expected dividend yield		0	%		0	%		0	%

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Granted		1,182,500		$	2.66
Exercised		-
Forfeited (1)		(2,606,289	)	$	2.79
Expired (1)		(2,400,590	)	$	6.51
Outstanding at September 30, 2019		772,847		$	4.89		7.3	$	-
Exercisable at September 30, 2019		476,390		$	6.13		6.4	$	-
Vested or expected to vest at September 30, 2019 (2)		772,847		$	4.89		7.3	$	-

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2017		2,681,072		$	7.18		6.8	$	121
Granted		2,041,600		$	2.61
Exercised		-
Forfeited		(83,433	)	$	5.82
Expired		(42,013	)	$	13.30
Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Exercisable at December 31, 2018		2,067,356		$	7.57		5.7	$	241
Vested or expected to vest at December 31, 2018 (1)		4,597,226		$	5.12		7.4	$	404

Note 10 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

	Year Ended December 31,
	2018			2017			2016
Domestic	$	(17,855	)	$	(24,803	)	$	(15,860	)
Foreign		(2,874	)		(5,161	)		(12,666	)
Total	$	(20,729	)	$	(29,964	)	$	(28,526	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended December 31,
	2018			2017			2016
Income tax benefit computed at federal statutory tax rate	$	(4,348	)	$	(10,186	)	$	(9,696	)
Permanent differences		6			4			430
Stock compensation - permanent items		325			689			-
R&D credit - permanent items		-			1,751			1,437
State income taxes, net of federal benefit		(958	)		(853	)		(498	)
Tax credits		(1,466	)		(5,495	)		(4,846	)
Change in valuation allowance		5,409			(54,319	)		8,804
Foreign rate differential		602			1,752			4,304
Rate change		-			2,202			-
382 limitation		-			64,975			-
Other		430			(520	)		65
Total	$	-		$	-		$	-

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	Year Ended December 31,
	2018			2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	6,742		$	2,651		$	37,237
Federal and state tax credits		3,122			2,244			21,223
Accrued expenses		411			399			544
Patents		132			191			360
Stock-based compensation		1,782			1,262			1,353
Other		169			202			321
Total deferred tax assets		12,358			6,949			61,038
Valuation allowance		(12,358	)		(6,949	)		(61,038	)
Net deferred assets	$	-		$	-		$	-

Note 11 - Net Loss Per Share Attributable to Common Stockholders (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Outstanding stock options		772,847		4,597,226		772,847		4,597,226
Outstanding ESPP shares		-		26,642		-		26,642
Convertible preferred stock		21,771,032		22,112,775		21,771,032		22,112,775
		22,543,879		26,736,643		22,543,879		26,736,643

	Year Ended December 31,
	2018		2017		2016
Outstanding stock options		4,597,226		2,681,072		2,166,254
Convertible preferred stock		22,112,775		22,112,775		-
		26,710,001		24,793,847		2,166,254

Note 12 - Quarterly Financial Information (Unaudited, in Thousands, Except Share and Per Share Data) (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Quarterly Financial Information [Table Text Block]

	Three Months Ended (a)
	March 31,			June 30,			September 30,			December 31,
	2018			2018			2018			2018
Operating expenses	$	6,365		$	5,000		$	4,622		$	5,385
Net loss attributable to common stockholders		(6,081	)		(4,879	)		(4,510	)		(5,259	)
Net loss per share attributable to common stockholders:
Basic and Diluted	$	(0.34	)	$	(0.28	)	$	(0.25	)	$	(0.27	)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders:
Basic and Diluted		17,674,729			17,674,729			17,824,186			19,221,292

	Three Months Ended (a)
	March 31,			June 30,			September 30,			December 31,
	2017			2017			2017			2017
Operating expenses	$	6,480		$	5,986		$	12,306		$	5,590
Net loss attributable to common stockholders		(6,498	)		(5,608	)		(19,054	)		(5,551	)
Net loss per share attributable to common stockholders:
Basic and Diluted	$	(0.39	)	$	(0.33	)	$	(1.08	)	$	(0.33	)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders:
Basic and Diluted		16,636,201			17,207,672			17,619,418	(b)		17,619,418

Note 1 - Organization and Operations (Details Textual) - USD ($)			3 Months Ended	12 Months Ended
	Aug. 02, 2017	Nov. 12, 2015	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019
Cash, Cash Equivalents, and Short-term Investments, Total				$ 21,900,000		$ 9,300,000
Retained Earnings (Accumulated Deficit), Ending Balance				$ (210,470,000)	$ (189,741,000)	$ (223,852,000)
Preferred Stock, Par or Stated Value Per Share				$ 0.001	$ 0.001	$ 0.001
Series A Convertible Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues	22,000
Payments of Stock Issuance Costs	$ 500,000
Preferred Stock, Par or Stated Value Per Share	$ 0.001			$ 0.001	$ 0.001
Shares Issued, Price Per Share	$ 1,000
Proceeds from Issuance of Convertible Preferred Stock	$ 22,000,000
Common Stock [Member]
Stock Issued During Period, Shares, New Issues			1,494,579	1,494,579	896,811
Sales Agreement [Member] \| Cowen and Company, LLC [Member] \| Common Stock [Member]
Sale of Stock, Maximum Value of Stock Offered		$ 40,000,000
Sale of Stock, Commission to Sales Agent, Percentage				3.00%
Stock Issued During Period, Shares, New Issues					896,811
Proceeds from Issuance of Common Stock					$ 1,400,000
Payments of Stock Issuance Costs					$ 100,000
Sales Agreement [Member] \| New Leaf Venture Partners LLC [Member] \| Common Stock [Member]
Stock Issued During Period, Shares, New Issues				1,494,579
Proceeds from Issuance of Common Stock				$ 3,000,000
Payments of Stock Issuance Costs				$ 46,000

Note 2 - Summary of Significant Accounting Policies - Property and Equipment Useful Lives (Details)	12 Months Ended
	Dec. 31, 2018
Computer Equipment and Software [Member]
Property and equipment, useful life (Year)	3 years
Furniture and Fixtures [Member]
Property and equipment, useful life (Year)	5 years
Laboratory Equipment [Member]
Property and equipment, useful life (Year)	7 years

Note 2 - Summary of Significant Accounting Policies (Details Textual)	9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Number of Operating Segments			1
Number of Reportable Segments			1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	$ (10,022,000)	$ (2,945,000)	$ (1,799,000)	$ (15,222,000)	$ (3,639,000)
Restricted Cash and Cash Equivalents, Total	22,000	22,000	22,000	22,000
Available-for-sale Securities, Gross Realized Gain (Loss), Total			0	0	0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total			0	0	$ 0
Liability for Uncertainty in Income Taxes, Current			0	0
Accounting Standards Update 2016-18 [Member]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	$ 22,000	$ 22,000	$ 22,000	$ 14,000

Note 3 - Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Total	$ 9,101	$ 20,849	$ 32,633
Cash Equivalents [Member]
Cash equivalents	9,101	18,353	11,662
US Government Agencies Debt Securities [Member]
Government securities		2,496	20,971
Fair Value, Inputs, Level 1 [Member]
Total	9,101	20,849	32,633
Fair Value, Inputs, Level 1 [Member] \| Cash Equivalents [Member]
Cash equivalents	9,101	18,353	11,662
Fair Value, Inputs, Level 1 [Member] \| US Government Agencies Debt Securities [Member]
Government securities		2,496	20,971
Fair Value, Inputs, Level 2 [Member]
Total
Fair Value, Inputs, Level 2 [Member] \| Cash Equivalents [Member]
Cash equivalents
Fair Value, Inputs, Level 2 [Member] \| US Government Agencies Debt Securities [Member]
Government securities
Fair Value, Inputs, Level 3 [Member]
Total
Fair Value, Inputs, Level 3 [Member] \| Cash Equivalents [Member]
Cash equivalents
Fair Value, Inputs, Level 3 [Member] \| US Government Agencies Debt Securities [Member]
Government securities

Note 3 - Fair Value Measurements - Available-for-sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost	$ 2,496	$ 20,991
Unrealized Gains
Unrealized Losses		(20)
Fair Value	2,496	20,971
US Government Agencies Debt Securities [Member]
Amortized Cost	2,496	20,991
Unrealized Gains
Unrealized Losses		(20)
Fair Value	$ 2,496	$ 20,971

Note 4 - Property and Equipment, Net - Summary of Property and Equipment (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and equipment		$ 1,090,000	$ 971,000
Accumulated depreciation		(827,000)	(712,000)
Property and equipment, net	0	263,000	259,000
Computer Equipment and Software [Member]
Property and equipment		211,000	192,000
Furniture and Fixtures [Member]
Property and equipment		365,000	302,000
Laboratory Equipment [Member]
Property and equipment		$ 514,000	$ 477,000

Note 4 - Property and Equipment, Net (Details Textual) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation, Total	$ 100,000	$ 22,000	$ 279,000	$ 83,000	$ 115,000	$ 148,000	$ 123,000

Note 5 - Accrued Expenses - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Payroll and employee-related costs		$ 1,390	$ 1,318
Contracted service costs		968	7,218
Professional fees and other		279	413
Total	$ 1,219	$ 2,637	$ 8,949

Note 6 - Commitments and Contingencies - Future Minimum Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2018 USD ($)
2019	$ 207
Total minimum lease payments	$ 207

Note 6 - Commitments and Contingencies (Details Textual)	1 Months Ended		12 Months Ended
	Aug. 31, 2017 ft²	Feb. 28, 2002	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Royalty Payment, Percentage of Net Sales		2.50%
Lessee, Operating Lease, Term of Contract	1 year 90 days
Operating Leases, Increase in Office Space \| ft²	2,552
Area of Real Estate Property \| ft²	7,500
Lessee, Operating Lease, Renewal Term	1 year
Operating Leases, Notice Required to Extend Term	180 days
Operating Leases, Rent Expense, Total			$ 300,000	$ 200,000	$ 200,000
Security Deposit			22,000				$ 22,000
Letters of Credit Outstanding, Amount			22,000	22,000		$ 22,000
Loans Pledged as Collateral			$ 22,000	$ 22,000		$ 22,000

Note 7 - Series A Preferred Financing (Details Textual) - USD ($)		12 Months Ended
	Aug. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2019
Preferred Stock, Par or Stated Value Per Share		$ 0.001	$ 0.001		$ 0.001
Preferred Stock, Shares Authorized		10,000,000	10,000,000		10,000,000
Accretion of Redeemable Convertible Preferred Stock to Redemption Value			$ 6,747,000
Series A Convertible Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues	22,000
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001	$ 0.001
Shares Issued, Price Per Share	$ 1,000
Proceeds from Issuance of Convertible Preferred Stock	$ 22,000,000
Payments of Stock Issuance Costs	$ 500,000
Convertible Preferred Stock, Shares Issued upon Conversion	1,005
Convertible Preferred Stock, Conversion Price of Shares Issued upon Conversion	$ 0.9949
Convertible Preferred Stock, Maximum Ownership Percentage Allowed after Conversion of Stock	9.985%
Preferred Stock, Shares Authorized		22,000	22,000		22,000
Preferred Stock, Redemption Price Per Share	$ 1.30
Accretion of Redeemable Convertible Preferred Stock to Redemption Value	$ 6,700,000
Preferred Stock, Liquidation Preference Per Share		$ 0.001

Note 8 - Common Stock - Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Reserved for future issuance (in shares)	28,707,366	27,394,852	25,877,695
The 2014 Employee Stock Purchase Plan [Member]
Reserved for future issuance (in shares)	118,120	118,120	192,463	140,500
Performance Shares [Member]
Reserved for future issuance (in shares)	6,818,214	5,163,957	3,572,457
Conversion of Series A Preferred Stock to Common Stock [Member]
Reserved for future issuance (in shares)	21,771,032	22,112,775	22,112,775

Note 8 - Common Stock (Details Textual) - $ / shares	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock, Shares Authorized	100,000,000	100,000,000	100,000,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001	$ 0.001
Common Stock, Shares, Issued, Total	19,585,394	19,243,651	17,674,729
Common Stock, Shares, Outstanding, Ending Balance	19,585,394	19,243,651	17,674,729

Note 9 - Stock-based Compensation - Black-scholes Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted average expected volatility	93.50%	94.50%	84.40%
Expected term (in years) (Year)	6 years 25 days	6 years 21 days	6 years 18 days
Risk free interest rate	2.55%	2.09%	1.45%
Expected dividend yield	0.00%	0.00%	0.00%

Note 9 - Stock-based Compensation (Details Textual) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2019	Jan. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term					6 years 146 days		5 years 255 days
Allocated Share-based Compensation Expense, Total			$ 96,000	$ 904,000	$ 977,000	$ 2,647,000	$ 3,429,000	$ 3,227,000	$ 3,343,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					1,182,500		2,041,600	719,337	132,495
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 2.61	$ 1.99	$ 5.08
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price					$ 2.66		$ 2.61		$ 7.11
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value							$ 0	$ 27,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options							$ 4,600,000	$ 4,200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition							2 years 146 days	2 years 146 days
Common Stock, Capital Shares Reserved for Future Issuance			28,707,366		28,707,366		27,394,852	25,877,695
Employee Stock Option [Member] \| Non-Employees [Member]
Allocated Share-based Compensation Expense, Total							$ 0	$ 0	$ 0
The 2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized							704,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Annual Additional Shares, Percentage							4.00%
The 2014 Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							3 years
The 2014 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							4 years
The 2006 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term							10 years
The 2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			192,436		192,436		304,991			140,500
Share-based Compensation Arrangement by Share-based Payment Award, Number of Annual Additional Shares, Percentage	1.00%						1.00%
Allocated Share-based Compensation Expense, Total							$ 100,000	$ 100,000	$ 100,000
Common Stock, Capital Shares Reserved for Future Issuance			118,120		118,120		118,120	192,463		140,500
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Additional Shares Authorizable	281,000	281,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		0
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			0		0		74,343	100,358

Note 9 - Stock-based Compensation - Stock-based Compensation Expense Recognized for Stock Options Granted (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allocated share-based compensation	$ 96	$ 904	$ 977	$ 2,647	$ 3,429	$ 3,227	$ 3,343
Research and Development Expense [Member]
Allocated share-based compensation	(26)	298	233	877	1,142	1,109	1,114
General and Administrative Expense [Member]
Allocated share-based compensation	$ 122	$ 606	$ 744	$ 1,770	$ 2,287	$ 2,118	$ 2,229

Note 9 - Stock-based Compensation - Stock Option Activity for Employees and Non-employees (Details) - USD ($)
$ / shares in Units, $ in Thousands

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Options Outstanding, Beginning Balance (in shares)

4,597,226

2,681,072

Options Outstanding, Weighted Average Exercise Price, Beginning Balance (in dollars per share)

$ 5.12

$ 7.18

Options Outstanding, Weighted-average Remaining Contractual Term (Year)

7 years 109 days

7 years 146 days

6 years 292 days

Options Outstanding, Aggregate Intrinsic Value

$ 404

$ 121

Options Granted (in shares)

1,182,500

2,041,600

719,337

132,495

Options Granted, Weighted Average Exercise Price (in dollars per share)

$ 2.66

$ 2.61

$ 7.11

Options Exercised, Weighted Average Exercise Price (in dollars per share)

Options Forfeited (in shares)

(2,606,289)

^[1]

(83,433)

Options Forfeited, Weighted Average Exercise Price (in dollars per share)

$ 2.79

^[1]

$ 5.82

Options Expired (in shares)

(2,400,590)

^[1]

(42,013)

Options Expired, Weighted Average Exercise Price (in dollars per share)

$ 6.51

^[1]

$ 13.30

Options Outstanding, Ending Balance (in shares)

772,847

4,597,226

2,681,072

Options Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)

$ 4.89

$ 5.12

$ 7.18

Options Exercisable (in shares)

476,390

2,067,356

Options Exercisable, Weighted Average Exercise Price (in dollars per share)

$ 6.13

$ 7.57

Options Exercisable, Weighted-average Remaining Contractual Term (Year)

6 years 146 days

5 years 255 days

Options Exercisable, Aggregate Intrinsic Value

$ 241

Options Vested or Expected to Vest (in shares)

772,847

^[2]

4,597,226

^[3]

Options Vested or Expected to Vest, Weighted Average Exercise Price (in dollars per share)

$ 4.89

^[2]

$ 5.12

^[3]

Options Vested or Expected to Vest, Weighted-average Remaining Contractual Term (Year)

7 years 109 days

^[2]

7 years 146 days

^[3]

Options Vested or Expected to Vest, Aggregate Intrinsic Value

^[2]

$ 404

^[3]

[1]	Represents the number of options cancelled during the nine months ended September 30, 2019 as a result of employees that were terminated due to the reduction in force.
[2]	Represents the number of vested options at September 30, 2019 plus the number of unvested options expected to vest based on the unvested options outstanding at September 30, 2019."
[3]	Represents the number of vested options at December 31, 2018 plus the number of unvested options expected to vest based on the unvested options outstanding at December 31, 2018.

Note 10 - Income Taxes - Summary of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net operating loss carryforwards	$ 6,742	$ 2,651	$ 37,237
Federal and state tax credits	3,122	2,244	21,223
Accrued expenses	411	399	544
Patents	132	191	360
Stock-based compensation	1,782	1,262	1,353
Other	169	202	321
Total deferred tax assets	12,358	6,949	61,038
Valuation allowance	(12,358)	(6,949)	(61,038)
Net deferred assets

Note 10 - Income Taxes - Domestic and Foreign Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Domestic	$ (17,855)	$ (24,803)	$ (15,860)
Foreign	(2,874)	(5,161)	(12,666)
Total	$ (20,729)	$ (29,964)	$ (28,526)

Note 10 - Income Taxes - Reconciliation of Income Taxes (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income tax benefit computed at federal statutory tax rate			$ (4,348)	$ (10,186)	$ (9,696)
Permanent differences			6	4	430
Stock compensation - permanent items			325	689
R&D credit - permanent items				1,751	1,437
State income taxes, net of federal benefit			(958)	(853)	(498)
Tax credits			(1,466)	(5,495)	(4,846)
Change in valuation allowance			5,409	(54,319)	8,804
Foreign rate differential			602	1,752	4,304
Rate change				2,202
382 limitation				64,975
Other			430	(520)	65
Total	$ 0	$ 0

Note 10 - Income Taxes (Details Textual) - USD ($)		9 Months Ended		12 Months Ended
Note 10 - Income Taxes (Details Textual) - USD ($)	Aug. 02, 2017	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Total		$ 0	$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%	34.00%
Deferred Tax Assets, Increase (Decrease) from Revaluation Due to Tax Rate Change					$ (2,200,000)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability					0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					(54,100,000)	8,800,000
Operating Loss Carryforwards, Net, Indefinite Lived				$ 14,700,000
Tax Credit Carryforward, Amount				3,100,000	2,300,000	0
Unrecognized Tax Benefits, Ending Balance				0	0	0
Current Year Deferred Tax Assets Activity [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount				5,400,000	13,100,000
Effect on Deferred Tax Assets of Section 382 Limitation [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					(65,000,000)
Effect of Tax Rate Change on Deferred Tax Assets [Member]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount					(2,200,000)
Series A Preferred Stock [Member]
Proceeds from Issuance of Convertible Preferred Stock	$ 22,000,000
Domestic Tax Authority [Member]
Income Tax Expense (Benefit), Total				0	0	0
Operating Loss Carryforwards, Total				25,700,000	10,600,000	0
Domestic Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Decrease in Net Operating Loss Carryforwards from Section 382 Limitation	107,300,000
Decrease in Net Operating Loss Carryforwards from Section 382 Limitation, Tax Affected	34,100,000
Decrease in Tax Credit Carryforward Amount from Section 382 Limitation	23,800,000
State and Local Jurisdiction [Member]
Income Tax Expense (Benefit), Total				0	0	0
Decrease in Net Operating Loss Carryforwards from Section 382 Limitation	5,000,000
Decrease in Tax Credit Carryforward Amount from Section 382 Limitation	$ 2,100,000
Operating Loss Carryforwards, Total				$ 21,500,000	$ 6,800,000	$ 0

Note 11 - Net Loss Per Share Attributable to Common Stockholders - Common Stock Equivalents Excluded From Calculation of Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities (in shares)	22,543,879	26,736,643	22,543,879	26,736,643	26,710,001	24,793,847	2,166,254
Convertible Preferred Stock [Member]
Antidilutive Securities (in shares)	21,771,032	22,112,775	21,771,032	22,112,775	22,112,775	22,112,775
Employee Stock Option [Member]
Antidilutive Securities (in shares)	772,847	4,597,226	772,847	4,597,226	4,597,226	2,681,072	2,166,254

Note 11 - Net Loss Per Share Attributable to Common Stockholders (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accretion of Redeemable Convertible Preferred Stock to Redemption Value		$ 6,747

Note 12 - Quarterly Financial Information (Unaudited, in Thousands, Except Share and Per Share Data) - Quarterly Financial Information (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Sep. 30, 2019

Sep. 30, 2018

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

us-gaap_OperatingExpenses

$ 1,591

$ 5,385

^[1]

$ 4,622

^[1]

$ 5,000

^[1]

$ 6,365

^[1]

$ 5,590

^[1]

$ 12,306

^[1]

$ 5,986

^[1]

$ 6,480

^[1]

$ 13,614

$ 15,987

$ 21,372

$ 30,362

$ 28,705

Net loss attributable to common stockholders

^[1]

$ (5,259)

$ (4,510)

$ (4,879)

$ (6,081)

$ (5,551)

$ (19,054)

$ (5,608)

$ (6,498)

Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)

$ (0.08)

$ (0.27)

^[1]

$ (0.25)

^[1]

$ (0.28)

^[1]

$ (0.34)

^[1]

$ (0.33)

^[1]

$ (1.08)

^[1]

$ (0.33)

^[1]

$ (0.39)

^[1]

$ (0.69)

$ (0.87)

$ (1.15)

$ (2.13)

$ (1.72)

Weighted-average common shares outstanding used in net loss per share attributable to common stockholders - basic and diluted (in shares)

19,585,394

19,221,292

^[1]

17,824,186

^[1]

17,674,729

^[1]

17,674,729

^[1]

17,619,418

^[1]

17,619,418

^[1],[2]

17,207,672

^[1]

16,636,201

^[1]

19,476,487

17,725,095

18,102,219

17,274,326

16,561,799

[1]	The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts.
[2]	Adjusted to correct an immaterial error in the weighted-average share calculation in the Company's Form 10-Q as of September 30, 2017.

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 9,349,000	$ 19,371,000	$ 21,170,000
Restricted cash	22,000
Available-for-sale investments		2,496,000	20,971,000
Prepaid expenses and other current assets	277,000	1,369,000	1,339,000
Total current assets	9,648,000	23,236,000	43,480,000
Property and equipment, net	0	263,000	259,000
Restricted cash		22,000	22,000
Total assets	9,648,000	23,521,000	43,979,000
Current liabilities:
Accounts payable	394,000	441,000	291,000
Accrued expenses	1,219,000	2,637,000	8,949,000
Total current liabilities	1,613,000	3,078,000	9,240,000
Total liabilities	1,613,000	3,078,000	9,240,000
Commitments and contingencies (Note 5)
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2019 and December 31, 2018: Series A convertible preferred stock 22,000 shares authorized at September 30, 2019 and December 31, 2018; 21,660 and 22,000 issued and outstanding at September 30, 2019 and at December 31, 2018, respectively
Common stock, $0.001 par value, 100,000,000 shares authorized at September 30, 2019 and December 31, 2018; 19,585,394 and 19,243,651 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	19,000	19,000	18,000
Additional paid-in capital	210,683,000	209,366,000	202,953,000
Accumulated deficit	(223,852,000)	(210,470,000)	(189,741,000)
Accumulated other comprehensive income	2,000	5,000	(14,000)
Total stockholders’ equity	8,035,000	20,443,000	34,739,000
Total liabilities and stockholders’ equity	9,648,000	23,521,000	43,979,000
Series A Convertible Preferred Stock [Member]
Current liabilities:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized at September 30, 2019 and December 31, 2018: Series A convertible preferred stock 22,000 shares authorized at September 30, 2019 and December 31, 2018; 21,660 and 22,000 issued and outstanding at September 30, 2019 and at December 31, 2018, respectively	$ 21,183,000	$ 21,523,000	$ 21,523,000

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 02, 2017
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	19,585,394	19,243,651	17,674,729
Common stock, shares outstanding (in shares)	19,585,394	19,243,651	17,674,729
Series A Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)		$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	22,000	22,000	22,000
Preferred stock, shares issued (in shares)	21,660	22,000	22,000
Preferred stock, shares outstanding (in shares)	21,660	22,000	22,000

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

^[1]

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

^[1]

Sep. 30, 2017

^[1]

Jun. 30, 2017

^[1]

Mar. 31, 2017

^[1]

Sep. 30, 2019

Sep. 30, 2018

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Operating expenses:

Research and development

$ 206

$ 2,354

$ 6,374

$ 9,185

$ 11,848

$ 21,686

$ 18,869

General and administrative

1,385

2,268

7,240

6,802

9,524

8,676

9,836

Total operating expenses

1,591

$ 5,385

4,622

^[1]

$ 5,000

^[1]

$ 6,365

^[1]

$ 5,590

$ 12,306

$ 5,986

$ 6,480

13,614

15,987

21,372

30,362

28,705

Loss from operations

(1,591)

(4,622)

(13,614)

(15,987)

(21,372)

(30,362)

(28,705)

Other income:

Investment income

113

231

311

436

259

193

Other income (expense), net

(1)

206

207

139

(14)

Total other income

112

232

517

643

398

179

Net loss

(1,536)

$ (5,315)

$ (6,531)

(4,510)

(4,879)

(6,081)

(13,382)

(15,470)

(20,729)

(29,964)

(28,526)

Foreign currency translation adjustment

(2)

(3)

(1)

Unrealized gain on available-for-sale investments

(20)

Comprehensive loss

(1,538)

(4,507)

(13,385)

(15,452)

(20,710)

(29,978)

(28,515)

Reconciliation of net loss to net loss attributable to common stockholders:

Net loss

(1,536)

$ (5,315)

$ (6,531)

(4,510)

$ (4,879)

$ (6,081)

(13,382)

(15,470)

(20,729)

(29,964)

(28,526)

Net loss attributable to common stockholders

$ (1,536)

$ (4,510)

$ (13,382)

$ (15,470)

$ (20,729)

$ (36,711)

$ (28,526)

Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)

$ (0.08)

$ (0.27)

$ (0.25)

^[1]

$ (0.28)

^[1]

$ (0.34)

^[1]

$ (0.33)

$ (1.08)

$ (0.33)

$ (0.39)

$ (0.69)

$ (0.87)

$ (1.15)

$ (2.13)

$ (1.72)

Weighted-average common shares outstanding used in net loss per share attributable to common stockholders - basic and diluted (in shares)

19,585,394

19,221,292

17,824,186

^[1]

17,674,729

^[1]

17,674,729

^[1]

17,619,418

^[2]

17,207,672

16,636,201

19,476,487

17,725,095

18,102,219

17,274,326

16,561,799

Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:

Allocated share-based compensation

$ 96

$ 904

$ 977

$ 2,647

$ 3,429

$ 3,227

$ 3,343

Research and Development Expense [Member]

Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:

Allocated share-based compensation

(26)

298

233

877

1,142

1,109

1,114

General and Administrative Expense [Member]

Included in operating expenses, above, are the following amounts for non-cash stock-based compensation expense:

Allocated share-based compensation

$ 122

$ 606

$ 744

$ 1,770

$ 2,287

$ 2,118

$ 2,229

[1]	The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts.
[2]	Adjusted to correct an immaterial error in the weighted-average share calculation in the Company's Form 10-Q as of September 30, 2017.

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member] Series A Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Series A Preferred Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Series A Preferred Stock [Member]	Total
Balance (in shares) at Dec. 31, 2015		16,501,500
Balance at Dec. 31, 2015		$ 16		$ 194,651	$ (131,251)	$ (11)		$ 63,405
Stock-based compensation expense				3,343				3,343
Net loss					(28,526)			(28,526)
Issuance of common stock upon ESPP purchase				11				11
Issuance of common stock upon ESPP purchase (in shares)		4,538
Balance (in shares) at Dec. 31, 2016		16,603,559
Balance at Dec. 31, 2016		$ 17		198,201	(159,777)			38,441
Stock-based compensation expense				3,227				3,227
Other comprehensive gain/(loss)						(14)		(14)
Net loss					(29,964)			(29,964)
Issuance of common stock upon ESPP purchase				130				130
Issuance of common stock upon ESPP purchase (in shares)		100,358
Issuance of common stock, net of issuance costs (in shares)	22,000	896,811
Issuance of common stock, net of issuance costs	$ 14,776	$ 1	$ 6,747	1,287			$ 21,523	1,288
Balance (in shares) at Dec. 31, 2017	22,000	17,674,729
Balance at Dec. 31, 2017	$ 21,523	$ 18		202,953	(189,741)	(14)		34,739
Stock-based compensation expense				821				821
Other comprehensive gain/(loss)						10		10
Net loss					(6,081)			(6,081)
Issuance of common stock upon ESPP purchase
Balance (in shares) at Mar. 31, 2018	22,000	17,674,729
Balance at Mar. 31, 2018	$ 21,523	$ 18		203,774	(195,822)	(4)		29,489
Balance (in shares) at Dec. 31, 2017	22,000	17,674,729
Balance at Dec. 31, 2017	$ 21,523	$ 18		202,953	(189,741)	(14)		34,739
Net loss								(15,470)
Balance (in shares) at Sep. 30, 2018	22,000	19,221,292
Balance at Sep. 30, 2018	$ 21,523	$ 19		208,536	(205,211)	4		24,871
Balance (in shares) at Dec. 31, 2017	22,000	17,674,729
Balance at Dec. 31, 2017	$ 21,523	$ 18		202,953	(189,741)	(14)		34,739
Stock-based compensation expense				3,429				3,429
Other comprehensive gain/(loss)						19		19
Net loss					(20,729)			(20,729)
Issuance of common stock upon ESPP purchase				132				132
Issuance of common stock upon ESPP purchase (in shares)		74,343
Issuance of common stock, net of issuance costs (in shares)		1,494,579
Issuance of common stock, net of issuance costs		$ 1		2,852				2,853
Balance (in shares) at Dec. 31, 2018	22,000	19,243,651
Balance at Dec. 31, 2018	$ 21,523	$ 19		209,366	(210,470)	5		20,443
Balance (in shares) at Mar. 31, 2018	22,000	17,674,729
Balance at Mar. 31, 2018	$ 21,523	$ 18		203,774	(195,822)	(4)		29,489
Stock-based compensation expense				922				922
Other comprehensive gain/(loss)						5		5
Net loss					(4,879)			(4,879)
Issuance of common stock upon ESPP purchase				84				84
Issuance of common stock upon ESPP purchase (in shares)		51,984
Balance (in shares) at Jun. 30, 2018	22,000	17,726,713
Balance at Jun. 30, 2018	$ 21,523	$ 18		204,780	(200,701)	1		25,621
Stock-based compensation expense				904				904
Other comprehensive gain/(loss)						3		3
Net loss					(4,510)			(4,510)
Issuance of common stock upon ESPP purchase
Issuance of common stock upon ESPP purchase (in shares)
Issuance of common stock, net of issuance costs (in shares)		1,494,579
Issuance of common stock, net of issuance costs		$ 1		2,852				2,853
Balance (in shares) at Sep. 30, 2018	22,000	19,221,292
Balance at Sep. 30, 2018	$ 21,523	$ 19		208,536	(205,211)	4		24,871
Balance (in shares) at Dec. 31, 2018	22,000	19,243,651
Balance at Dec. 31, 2018	$ 21,523	$ 19		209,366	(210,470)	5		20,443
Conversion of Series A convertible preferred stock into Common Stock (in shares)	(340)
Conversion of Series A convertible preferred stock into Common Stock	$ (340)
Conversion of Series A convertible preferred stock into Common Stock (in shares)		341,743
Conversion of Series A convertible preferred stock into Common Stock				340
Stock-based compensation expense				780				780
Other comprehensive gain/(loss)						(2)		(2)
Net loss					(6,531)			(6,531)
Balance (in shares) at Mar. 31, 2019	21,660	19,585,394
Balance at Mar. 31, 2019	$ 21,183	$ 19		210,486	(217,001)	3		14,690
Balance (in shares) at Dec. 31, 2018	22,000	19,243,651
Balance at Dec. 31, 2018	$ 21,523	$ 19		209,366	(210,470)	5		20,443
Net loss								(13,382)
Balance (in shares) at Sep. 30, 2019	21,660	19,585,394
Balance at Sep. 30, 2019	$ 21,183	$ 19		210,683	(223,852)	2		8,035
Balance (in shares) at Mar. 31, 2019	21,660	19,585,394
Balance at Mar. 31, 2019	$ 21,183	$ 19		210,486	(217,001)	3		14,690
Conversion of Series A convertible preferred stock into Common Stock
Conversion of Series A convertible preferred stock into Common Stock
Stock-based compensation expense				101				101
Other comprehensive gain/(loss)						1		1
Net loss					(5,315)			(5,315)
Balance (in shares) at Jun. 30, 2019	21,660	19,585,394
Balance at Jun. 30, 2019	$ 21,183	$ 19		210,587	(222,316)	4		9,477
Conversion of Series A convertible preferred stock into Common Stock
Conversion of Series A convertible preferred stock into Common Stock
Stock-based compensation expense				96				96
Other comprehensive gain/(loss)						(2)		(2)
Net loss					(1,536)			(1,536)
Balance (in shares) at Sep. 30, 2019	21,660	19,585,394
Balance at Sep. 30, 2019	$ 21,183	$ 19		$ 210,683	$ (223,852)	$ 2		$ 8,035

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net loss	$ (13,382,000)	$ (15,470,000)
Reconciliation of net loss to net cash used in operating activities:
Depreciation	279,000	83,000
Amortization of discount on available-for-sale securities	(4,000)	(35,000)
Foreign currency remeasurement loss	(3,000)	(25,000)
Stock-based compensation	977,000	2,647,000
Changes in:
Prepaid expenses and other assets	1,082,000	589,000
Operating lease right-of-use asset	200,000
Interest receivable	10,000	(3,000)
Accounts payable and accrued expenses	(1,465,000)	(6,706,000)
Operating lease liability	(200,000)
Net cash used in operating activities	(12,506,000)	(18,920,000)
Investing activities
Purchases of available-for-sale investments		(12,951,000)
Proceeds from maturities of available-for-sale investments	2,500,000	23,990,000
Proceeds from sale of available-for-sale investments		1,999,000
Purchase of property and equipment	(16,000)	(24,000)
Net cash provided by investing activities	2,484,000	13,014,000
Financing activities
Proceeds from issuance of common stock, net of issuance costs		2,853,000
Proceeds from issuance of common stock under ESPP		84,000
Net cash provided by financing activities		2,937,000
Effect of exchange rate changes on cash		24,000
Decrease in cash, cash equivalents and restricted cash	(10,022,000)	(2,945,000)
Cash, cash equivalents and restricted cash, beginning of period	19,393,000	21,192,000
Cash, cash equivalents and restricted cash, end of period	$ 9,371,000	$ 18,247,000

Note 1 - Organization and Operations

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Nature of Operations [Text Block]

Organization and Operations

The Company

Proteon Therapeutics, Inc. (the “Company”) is a biopharmaceutical company that has historically focused on the development of novel,

first

-in-class pharmaceuticals to address the medical needs of patients with kidney and vascular disease. The Company was formed in

June 2001

and incorporated on

March 24, 2006.

March 28, 2019,

the Company announced that its

second

Phase

trial, PATENCY-

for vonapanitase did

not

meet its co-primary endpoints of fistula use for hemodialysis (

p=0.328

) and secondary patency (

p=0.932

). The PATENCY-

clinical trial was the

second

two

randomized, double-blind Phase

trials, comparing a

clinical trial of vonapanitase on

March 28, 2019,

not

April 15, 2019,

the Company announced the engagement of H.C. Wainwright & Co., LLC as its financial advisor to assist in the strategic review process. Since these efforts

may

not

be successful, the Company is also considering other possible alternatives, including a wind-down of operations and a liquidation and dissolution of the Company. On

September 23, 2019,

September 30, 2019,

the Company has terminated all but

one

of its employees. The Company has recorded severance costs of

$2.9

million, all of which was recorded in the

three

months ended

June 30, 2019.

These severance related expenses were fully recorded in the

three

months ending

June 30, 2019.

third

parties and product liability.

Liquidity and Going Concern

As of

September 30, 2019,

the Company had cash and cash equivalents of

$9.3

million. The Company believes that its existing cash and cash equivalents will be sufficient to fund its projected cash needs into

2020

and enable it to complete the proposed merger with ArTara, pursuant to which REM

Acquisition

may

prevent it from completing the Merger. Accordingly, these factors, among others, raise substantial doubt about the Company’s ability to continue as a going concern.

The Company had an accumulated deficit of

$223.9

million as of

September 30, 2019.

second

Phase

trial, PATENCY-

for vonapanitase did

not

These conditions raise substantial doubt about its ability to continue as a going concern within

one

assurance that the Company will be able to achieve its future strategic alternatives raising substantial doubt about its ability to continue as a going concern.

Pursuant to the requirements of Accounting Standards Codification (ASC)

205

40,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within

one

year after the date that the financial statements are issued. This evaluation initially does

not

take into consideration the potential mitigating effect of management’s plans that have

not

) it is probable that the plans will be effectively implemented within

one

year after the date that the financial statements are issued, and (

) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within

one

year after the date that the financial statements are issued.

Under ASC

2015

40,

the strategic alternatives being pursued by the Company, including the Merger, cannot be considered probable at this time because

none

of the Company’s current plans have been finalized at the time of filing this Quarterly Report on Form

-Q and the implementation of any such plan is

not

probable of being effectively implemented as

none

of the plans are entirely within the Company’s control. Accordingly, substantial doubt is deemed to exist about the Company’s ability to continue as a going concern within

one

year after the date these financial statements are issued.

not

Merger Agreement

September 23, 2019,

The Merger is intended to qualify for U.S. federal income tax purposes as a reorganization under the provisions of Section

368

(a) of the Internal Revenue Code of

1986,

as amended.

As promptly as practicable after the date of the Merger Agreement (but in

event later than

days following the date of the Merger Agreement), the parties will prepare and the Company will file with the U.S. Securities and Exchange Commission (“SEC”) a Registration Statement on Form S-

one

new share for every

9.985%

beneficial ownership cap) (the “Series A Preferred Automatic Conversion”); and

an amendment to the Company’s Amended and Restated

2014

not

exceed

15.2%

less than

$40.0

million to be committed thereunder and (viii) the Company having at least

in net cash as of the closing date of the Merger (the “Company Net Cash condition”).

may

be required to pay to ArTara a termination fee of

$0.8

million or ArTara

may

be required to pay to the Company a termination fee of

$0.8

million, and in other circumstances each party

may

be required to reimburse the other party's expenses incurred, up to a maximum of

$0.4

million.

180

-day period following the closing of the Merger.

seven

members, with

five

such members designated by ArTara,

one

such member designated by the Company, and

one

such member who will be Mr. Jesse Shefferman, the Chief Executive Officer of the combined company.

Private Placement

In connection with the Merger, on

September 23, 2019,

27,200

shares of the Company’s Series

Convertible Non-Voting Preferred Stock, par value

$0.001

per share (the “Series

Preferred Stock”), at a purchase price equal to

1,000

times the Common Stock Purchase Price (as defined below) and (ii) up to

15,300

shares of the Company’s common stock (together with the Series

Preferred Stock, the “Private Placement Shares”), at a purchase price equal to (

) the Aggregate Valuation (as defined in the Merger Agreement) divided by the (y) the Post-Closing Parent Shares (as defined in the Merger Agreement) (the “Common Stock Purchase Price”).

Pursuant to the Subscription Agreement, the holders of Series

not

Prior to the issuance of the Private Placement Shares, the Company intends to file a Certificate of Designation of Preferences, Rights and Limitations of Series

Convertible Non-Voting Preferred Stock (the "Certificate of Designation") with the Delaware Secretary of State. Thereunder, each share of Series

Preferred Stock will be convertible into

1,000

(d) of the Exchange Act would beneficially own more than

9.99%

of the total number of shares of the Company’s common stock issued and outstanding after giving effect to such conversion. Upon written notice to the Company, the holder

may

from time to time increase or decrease such limitation to any other percentage

not

in excess of

19.99%

specified in such notice.

Each share of Series

Preferred Stock will be entitled to a preference of

$10.00

one

share of Series

Preferred Stock would receive in connection with such transaction.

The Private Placement is expected to close immediately following the consummation of the Merger.

Organization and Operations

The Company

Proteon Therapeutics, Inc. (the “Company”) is a late-stage biopharmaceutical company focused on the development of novel,

first

-in-class pharmaceuticals to address the medical needs of patients with kidney and vascular disease. The Company was formed in

June 2001

and incorporated on

March 24, 2006.

The Company devotes substantially all of its efforts to product research and development, initial market development and raising capital. The Company has

not

third

parties and product liability.

Liquidity and Going Concern

As of

December 31, 2018,

the Company had cash, cash equivalents and available-for-sale investments of

$21.9

million. The Company believes that its existing cash, cash equivalents and available-for-sale investments will be sufficient to fund operations and capital expenditures into the

first

quarter of

2020.

The Company had an accumulated deficit of

$210.5

million as of

December 31, 2018.

Based on these available cash resources, the Company does

not

have sufficient cash on hand to support current operations for at least the next

twelve

months from the date of filing this Annual Report on Form

-K. This condition raises substantial doubt about the Company’s ability to continue as a going concern.

The Company’s plans to address this condition include pursuing

one

or more of the following options to secure additional funding,

none

of which can be guaranteed or are entirely within our control:

•

raise additional funding through the possible sale of additional shares of the Company’s common stock, including public or private equity financings, and/or possible debt financings; and

•

There can be

twelve

months from the date of filing this Annual Report on Form

-K.

Pursuant to the requirements of Accounting Standards Codification (ASC)

205

40,

Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern

management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within

one

year after the date that the financial statements are issued. This evaluation initially does

not

take into consideration the potential mitigating effect of management’s plans that have

not

) it is probable that the plans will be effectively implemented within

one

year after the date that the financial statements are issued, and (

) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within

one

year after the date that the financial statements are issued.

Under ASC

2015

40,

the future receipt of potential funding from the Company’s partners and other resources cannot be considered probable at this time because

none

of the Company’s current plans have been finalized at the time of filing this Annual Report on Form

-K and the implementation of any such plan is

not

probable of being effectively implemented as

none

of the plans are entirely within the Company’s control. Accordingly, substantial doubt is deemed to exist about the Company’s ability to continue as a going concern within

one

year after the date these financial statements are issued.

The Company believes that its approximate

$21.9

million in cash, cash equivalents and marketable securities at

December

31,

2018,

as described above, would allow it to fund its planned operations into the

first

quarter of

2020.

This estimate assumes

equity financings,

debt financings and

funding from new partnership agreements. Accordingly, the timing and nature of activities contemplated for the remainder of

2019

and thereafter will be conducted subject to the availability of sufficient financial resources.

If the Company is unable to obtain sufficient capital to continue to advance its programs, the Company would be forced to delay, reduce or eliminate its ongoing development and other activities.

not

At-The-Market Equity Offering Program

November 12, 2015,

the Company filed a shelf registration statement on Form S-

$40

million of the Company’s Common Stock at prevailing market prices from time to time. The Registration Statement became effective on

January 12, 2016.

The Company paid Cowen a commission equal to

March 16, 2017

because the Company is currently subject to General Instruction

I.B.6

of Form S-

which limits the amounts that the Company

may

sell under the Registration Statement. The Company’s ATM program was terminated effective as of

February 7, 2019,

when its new shelf registration statement on Form S-

File

No.

333

228865,

was declared effective by the SEC. For the year ended

December 31, 2017,

the Company sold

896,811

shares of Common Stock under the Sales Agreement for aggregate gross proceeds of

$1.4

million offset by total offering costs of

$0.1

million. For the year ended

December 31, 2018,

the Company sold

1,494,579

shares of Common Stock under the Sales Agreement for aggregate gross proceeds of

$3.0

million. For the year ended

December 31, 2018,

total offering costs of

$46,000,

were offset against the proceeds from the sale of common stock. The

1,494,579

shares of Common Stock sold under the ATM program during the year ended

December 31, 2018

were all sold on

September 25, 2018

to New Leaf Venture Partners LLC.

Series A Preferred Financing

June 22, 2017,

22,000

shares of the Company’s Series A Convertible Preferred Stock, par value

$0.001

per share (the “Transaction”), for a purchase price of

$1,000

per share, or an aggregate gross purchase price of

$22.0

million, all upon the terms and conditions set forth in the Purchase Agreement. The Company closed this Transaction on

August 2, 2017 (

see Note

August 2, 2017,

the Company entered into a registration rights agreement with the Investors (the “Registration Rights Agreement”). On

August 3, 2017,

in accordance with the Registration Rights Agreement, the Company filed a registration statement on Form S-

to register the common stock issuable upon conversion of the Preferred Shares. The registration statement became effective on

August 21, 2017.

Note 2 - Summary of Significant Accounting Policies

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Significant Accounting Policies [Text Block]

Summary of Significant Accounting Policies

Basis of Presentation, Principles of Consolidation and Use of Estimates

December 31, 2018

and notes thereto, included in the Company’s Annual Report on Form

-K, as filed with the SEC on

March 13, 2019.

September 30, 2019,

the results of its operations for the

three

and

nine

months ended

September 30, 2019

and

2018,

results of changes in stockholders equity for the

nine

months ended

September 30, 2019

and

2018,

and its cash flows for the

nine

months ended

September 30, 2019

and

2018.

Such adjustments are of a normal and recurring nature. The results for the

three

and

nine

months ended

September 30, 2019

are

not

necessarily indicative of the results for the year ending

December 31, 2019,

or for any future period.

not

may

differ from those estimates or assumptions.

Fair Value of Financial Instruments

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents and available-for-sale investments. There have been

changes to the valuation methods utilized by the Company during the

three

and

nine

months ended

September 30, 2019

and

2018.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the

three

and

nine

months ended

September 30, 2019

and

2018.

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers (“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

2016

January 1, 2019

using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and will

not

restate prior periods. It has have also elected to adopt the package of practical expedients permitted in Accounting Standards Codification Topic

842,

or ASC

842.

Accordingly, it is continuing to account for its existing operating lease as an operating lease under the new guidance, without reassessing whether the contract contains a lease under ASC

842

or whether classification of the operating leases would be different under ASC Topic

842,

and to treat lease and non-lease components as a single lease component. The Company’s sole lease at the adoption date was an operating lease for facilities and did

not

include any non-lease components.

As a result of the adoption of ASU

2016

02,

January 1, 2019,

the Company recognized (a) a lease liability of approximately

$0.2

million, which represents the present value of its remaining lease payments using an estimated incremental borrowing rate of

8%,

(b) a right-of-use asset of approximately

$0.2

million that will be expensed as operating lease expense over the term of the lease. Due to the adoption of the standard using the retrospective cumulative-effect adjustment method, there are

changes to previously reported results prior to

January 1, 2019.

Lease expense is

not

expected to change materially as a result of the adoption of ASU

2016

02.

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments (“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and the ending balances by

$22,000

for both the

nine

months ended

September 30, 2019

and

2018.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting (“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company adopted ASU

2018

during the quarter ended

March 31, 2019.

The adoption did

not

have an impact on the condensed consolidated financial statements as all outstanding non-employee share-based awards had vested prior to

March 31, 2018.

Summary of Significant Accounting Policies

Basis of Presentation, Principles of Consolidation and Use of Estimates

not

may

differ from those estimates or assumptions.

Segment Information

one

operating segment, which is the business of developing and commercializing vonapanitase for the treatment of renal and vascular disease. Currently, the Company operates in only

one

geographic segment.

Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, available-for-sale investments, forward foreign currency contracts (see Note

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents, available-for-sale investments and forward foreign currency contracts (see Note

). There have been

changes to the valuation methods utilized by the Company during the years ended

December 31, 2018

and

2017.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the years ended

December 31, 2018

and

2017.

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers

(“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

January 1, 2019

not

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments

(“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

Statement of Cash Flows, Restricted Cash

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and

$14,000

for the years ended

December 31, 2018

and

2017,

respectively. The ending balances were increased by

$22,000

for both the years ended

December 31, 2018

and

2017.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting

(“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company is currently evaluating the impact of the new guidance on its condensed consolidated financial statements.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of

days or less from the purchase date to be cash equivalents. Cash and cash equivalents are held in depository and money market accounts and are reported at fair value.

Short-Term Investments

one

year. There have been

realized gains and losses for the years ended

December 31, 2018,

2017

and

2016.

other-than-temporary declines in value of short-term investments for the years ended

December 31, 2018,

2017

and

2016,

as it is more likely than

not

the Company will hold the securities until maturity or a recovery of the cost basis.

Concentrations of Credit Risk and Off-Balance Sheet Risk

may

exceed federally insured limits. The Company has

not

experienced any credit losses in such accounts and does

not

believe it is exposed to any significant credit risk on these funds. The Company has

financial instruments with off-balance sheet risk of loss.

Property and Equipment

Property and equipment is stated at cost, less accumulated depreciation. Maintenance and repairs that do

not

not,

Asset	Estimated Useful Life (in years)
Computer equipment and software		3
Furniture, fixtures and other		5
Laboratory equipment		7

Research and Development Costs

Stock-Based Compensation Expense

The Company accounts for its stock-based compensation awards to employees and directors in accordance with FASB ASC Topic

718,

Compensation-Stock Compensation

(“ASC

718”

). ASC

718

and FASB ASC Topic

505,

Equity

and are expensed using an accelerated attribution model.

2018

not

expect to pay dividends in the foreseeable future. Refer to Note

“

Use of Estimates

,” for a discussion of the Company's estimated fair value of its Common Stock.

Income Taxes

Income taxes are recorded in accordance with FASB ASC Topic

740,

“Income Taxes” (“ASC

740”

not

that some or all of the deferred tax assets will

not

be realized. The Company has evaluated available evidence and concluded that the Company

may

not

realize the benefit of its deferred tax assets; therefore, a valuation allowance has been established for the full amount of the deferred tax assets.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC

740.

When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than

not

be realized. The determination as to whether the tax benefit will more likely than

not

be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of

December 31, 2018

and

2017,

the Company did

not

have any significant uncertain tax positions. The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. See Note

for further details.

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

Comprehensive Loss

Subsequent Events

December 31, 2018

to ensure that this filing includes appropriate disclosure of events both recognized in the consolidated financial statements as of

December 31, 2018

and events which occurred subsequently but were

not

recognized in the consolidated financial statements.

Note 3 - Fair Value Measurements

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Fair Value Disclosures [Text Block]

Fair Value Measurements

Below is a summary of assets and liabilities measured at fair value (in thousands):

	As of September 30, 2019
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	9,101	$	-	$	-	$	9,101
Total	$	9,101	$	-	$	-	$	9,101

	As of December 31, 2018
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

As of

September 30, 2019

and

December 31, 2018,

the Company’s cash equivalents consist principally of money market funds and government debt securities with original maturities of

days or less. Government securities consist principally of government debt securities and money market funds which are classified as available-for-sale.

Available-for-sale securities at

September 30, 2019

and

December 31, 2018

consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
September 30, 2019
Government securities
(Due within 1 year)	$	-	$	-	$	-	$	-
	$	-	$	-	$	-	$	-

December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-	$	2,496
	$	2,496	$	-	$	-	$	2,496

Fair Value Measurements

Below is a summary of assets and liabilities measured at fair value (in thousands):

	As of December 31, 2018
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2017
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	11,662	$	-	$	-	$	11,662
Government securities		20,971		-		-		20,971
Total	$	32,633	$	-	$	-	$	32,633

As of

December 31, 2018,

and

2017,

the Company’s cash equivalents consist principally of money market funds and government debt securities with original maturities of

days or less. Government securities consist principally of government debt securities and money market funds which are classified as available-for-sale.

Available-for-sale securities at

December 31, 2018

and

2017

consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-		$	2,496
	$	2,496	$	-	$	-		$	2,496

December 31, 2017
Government securities
(Due within 1 year)	$	20,991	$	-	$	(20	)	$	20,971
	$	20,991	$	-	$	(20	)	$	20,971

- Definition

+ References + Details

Note 4 - Property and Equipment, Net

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	As of
	September 30, 2019		December 31, 2018

Computer equipment and software	$	-	$	211
Furniture, fixtures, and other		-		365
Laboratory equipment		-		514
		-		1,090
Accumulated depreciation		-		(827	)
Property and equipment, net	$	-	$	263

Depreciation expense for the

three

and

nine

months ended

September 30, 2019

was

$0.1

million, and

$0.3

million, respectively. Depreciation expense for the

three

and

nine

months ended

September 30, 2018

was

$22,000,

and

$0.1

million, respectively.

During the

three

months ended

March 31, 2019,

the Company voluntarily discontinued substantially all research and development activities. As a result, as of

March 31, 2019

March 31, 2019.

As of

September 30, 2019,

future use for the assets. The Company recorded an impairment charges of

zero

and

$0.2

million during the

three

and

nine

months ended

September 30, 2019.

As of

September 30, 2019,

property and equipment balance remained as a result of the impairment.

Property and Equipment, net

Property and equipment, net consists of the following (in thousands):

	As of December 31,
	2018			2017

Computer equipment and software	$	211		$	192
Furniture, fixtures, and other		365			302
Laboratory equipment		514			477
		1,090			971
Accumulated depreciation		(827	)		(712	)
Property and equipment, net	$	263		$	259

Depreciation expense for the years ended

December 31, 2018,

2017

and

2016

was

$0.1

million,

$0.1

million, and

$0.1

million, respectively.

Note 5 - Commitments and Contingencies

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

Commitments and Contingencies

Operating Lease

The Company’s facility is located in Waltham, Massachusetts. In

July 2018,

it amended the lease extending its expiration to

September 2019.

During the

three

and

nine

months ended

September 30, 2019,

it recognized operating lease expense of

$0.1

million and

$0.2

million, respectively including property taxes and routine maintenance expense, which approximated its cash payments for the period. The lease expired as of

September 30, 2019,

and therefore the condensed consolidated balance sheet does

not

include an operating lease right-of-use asset or an operating lease liability in other assets and other current liabilities, respectively. As of

September 30, 2019,

there are

future minimum payments required under the operating lease. As of

September 30, 2019,

the Company has provided a security deposit in the amount of

$22,000

to the lessor. The security deposit will be returned within

days of the expiration of the lease which occurred on

September 30, 2019.

Restricted cash related to facilities leases

As of

September 30, 2019

and

December 31, 2018,

the Company had

$22,000

in an outstanding letter of credit to be used as collateral for leased premises. As of

September 30, 2019

and

December 31, 2018,

the Company pledged an aggregate of

$22,000

to the bank as collateral for the letter of credit, which is included in other current assets and non-current assets, respectively. The security deposit will be returned within

days of the expiration of the lease which occurred on

September 30, 2019.

Commitments and Contingencies

Significant Contracts and Agreements

February 2002,

2.5%

on net sales of the product. As of

December 31, 2018

the Company has

not

commenced product sales and therefore has recognized

royalties on product sales.

Operating Leases

The Company has various non-cancellable operating leases for facilities and office equipment that expire at various dates through

2019.

August 2017,

the Company entered into an Amendment (the “Lease Amendment”) to the existing Lease Agreement dated

July 13, 2009 (

the “Lease Agreement”), with Boston Properties Limited Partnership (“Lessor”) pursuant to which the Company has agreed to (i) extend the term of the lease for a period of

fifteen

(

) months from

June 30, 2018

until

September 30, 2019

and (ii) increase the Company’s office space under the Lease Agreement by

2,552

square feet of additional property for a total of approximately

7,500

square feet of property (the “Leased Property”). The Leased Property is located at

200

West St., Waltham, Massachusetts. In addition, the Company has the option to extend the term of the Lease Agreement for an additional

one

-year period upon the Company’s written notice to the Lessor at least

six

months prior to the expiration of the term. Rental expense was

$0.3

million,

$0.2

million and

$0.2

million for the years ended

December 31, 2018,

2017

and

2016,

respectively.

Future minimum payments required under operating leases as of

December 31, 2018

are summarized as follows (in thousands):

Year Ending December 31:	Amount

2019		207
Total minimum lease payments	$	207

In addition to the base rent, the Company is also responsible for its share of operating expenses and real estate taxes, in accordance with the terms of the lease agreement. As of

December 31, 2018,

the Company has provided a security deposit in the amount of

$22,000

to the lessor.

Restricted cash related to facilities leases

December 31, 2018

and

2017,

the Company had

$22,000

respectively, in an outstanding letter of credit to be used as collateral for leased premises. At

December 31, 2018

and

2017,

the Company pledged an aggregate of

$22,000

to the bank as collateral for the letter of credit, which is included in other non-current assets.

Note 6 - Stock-based Compensation

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Share-based Payment Arrangement [Text Block]

Stock-based Compensation

Stock Options

The following table summarizes stock option activity for employees:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Granted		1,182,500		$	2.66
Exercised		-
Forfeited (1)		(2,606,289	)	$	2.79
Expired (1)		(2,400,590	)	$	6.51
Outstanding at September 30, 2019		772,847		$	4.89		7.3	$	-
Exercisable at September 30, 2019		476,390		$	6.13		6.4	$	-
Vested or expected to vest at September 30, 2019 (2)		772,847		$	4.89		7.3	$	-

_____________________

(

) Represents the number of options cancelled during the

nine

months ended

September 30, 2019

as a result of employees that were terminated due to the reduction in force.

(

) Represents the number of vested options at

September 30, 2019

plus the number of unvested options expected to vest based on the unvested options outstanding at

September 30, 2019.

Employee Stock Purchase Plan

The

2014

Employee Stock Purchase Plan (ESPP) initially authorized the issuance of up to

140,500

shares of Common Stock. The number of shares increases each

January 1,

commencing on

January 1, 2015

and ending on (and including)

January 1, 2024,

by an amount equal to the lesser of

one

percent of the outstanding shares as of the end of the immediately preceding fiscal year,

281,000

shares and any lower amount determined by the Company’s Board of Directors prior to each such

January

1st.

As of

September 30, 2019,

as a result of an increase on

January 1, 2019

one

percent of the outstanding shares as of the end of the fiscal year ending

December 31, 2018,

the

2014

ESPP authorized the issuance of up to

192,436

shares of Common Stock. The

tenth

offering under the

2014

ESPP began on

July 1, 2019

and ended on

September 30, 2019.

shares were issued during the

three

and

nine

months ended

September 30, 2019.

shares and

51,984

shares were issued during the

three

and

nine

months ended

September 30, 2018

under the

2014

ESPP. The Company incurred

zero

and

$68,000

in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2019

respectively. The Company incurred

$20,000

and

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the

three

and

nine

months ended

September 30, 2018,

respectively.

Common Stock

The Company has the following shares of Common Stock reserved for future issuance:

	September 30,		December 31,
	2019		2018

Conversion of Series A Preferred Stock		21,771,032		22,112,775
Stock-based compensation awards		6,818,214		5,163,957
Employee Stock Purchase Plan		118,120		118,120
Total		28,707,366		27,394,852

Stock-based Compensation

August 21, 2014,

the Company’s Board of Directors superseded the

2006

Equity Incentive Plan (the

“2006

Plan”) with the

2014

Equity Incentive Plan (the

“2014

Plan”), and the

2014

Employee Stock Purchase Plan (the

“2014

ESPP”). On

October 3, 2014,

the stockholders approved these plans. The stockholders also approved an amendment to the

2014

Plan on

July 31, 2017.

2006

Plan,

new stock compensation awards will be granted subsequent to the completion of the Company’s IPO. The Company initially reserved

704,000

shares of Common Stock for issuance under the

2014

Plan. The

2014

Plan provides that the number of shares reserved and available for issuance under the

2014

Plan will automatically increase each

January 1,

beginning

January 1, 2015

four

percent of the outstanding shares of Common Stock on the immediately preceding

December 31

or such lesser number of shares as determined by the Company’s Board of Directors prior to each such

January

1st.

Terms of the stock awards, including vesting requirements, are determined by the Board of Directors, subject to the provisions of the Plans. Options granted by the Company typically vest over

three

four

years. Certain awards provide for accelerated vesting if there is a change in control as defined in the Plans. Stock options outstanding under the

2006

Plan are exercisable from the date of grant for a period of

ten

years. Stock options granted under the

2014

Plan are exercisable only upon vesting. For options granted to date, the exercise price equaled the fair value of the Common Stock as determined by the Board of Directors on the date of grant.

Stock-based compensation expense

	Year Ended December 31,
	2018		2017		2016

Research and development	$	1,142	$	1,109	$	1,114
General and administrative		2,287		2,118		2,229
Total	$	3,429	$	3,227	$	3,343

	Year Ended December 31,
	2018			2017			2016
Weighted average expected volatility		93.5	%		94.5	%		84.4	%
Expected term (in years)		6.07			6.06			6.05
Risk free interest rate		2.55	%		2.09	%		1.45	%
Expected dividend yield		0	%		0	%		0	%

for the years ended

December 31, 2018,

2017

and

2016.

Stock Options

The following table summarizes stock option activity for employees and non-employees:

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2017		2,681,072		$	7.18		6.8	$	121
Granted		2,041,600		$	2.61
Exercised		-
Forfeited		(83,433	)	$	5.82
Expired		(42,013	)	$	13.30
Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Exercisable at December 31, 2018		2,067,356		$	7.57		5.7	$	241
Vested or expected to vest at December 31, 2018 (1)		4,597,226		$	5.12		7.4	$	404

__________________

(

) Represents the number of vested options at

December 31, 2018

plus the number of unvested options expected to vest based on the unvested options outstanding at

December 31, 2018.

During the year ended

December 31, 2018,

the Company granted stock options to purchase an aggregate of

2,041,600

shares of its Common Stock with a weighted-average grant date fair value of

$2.61.

During the year ended

December 31, 2017,

the Company granted stock options to purchase an aggregate of

719,337

shares of its Common Stock with a weighted-average grant date fair value of

$1.99.

During the year ended

December 31, 2016,

the Company granted stock options to purchase an aggregate of

132,495

shares of its Common Stock with a weighted-average exercise price of

$7.11

and a weighted-average grant date fair value of

$5.08.

The total intrinsic value of options exercised in the years ended

December 31, 2018

and

2017

was

and

$27,000

respectively. As of

December 31, 2018,

and

2017

there was

$4.6

million and

$4.2

2.40

years.

Employee Stock Purchase Plan

The

2014

Employee Stock Purchase Plan (“ESPP”) initially authorized the issuance of up to

140,500

shares of Common Stock. The number of shares increases each

January 1,

commencing on

January 1, 2015

and ending on (and including)

January 1, 2024,

by an amount equal to the lesser of

one

percent of the outstanding shares as of the end of the immediately preceding fiscal year,

281,000

shares or any lower amount determined by the Company’s Board of Directors prior to each such

January

1st.

The Company’s Board of Directors determined there was to be

increase on

January 1, 2018.

As of

December 31, 2018,

the

2014

ESPP authorized the issuance of up to

304,991

shares of Common Stock. The

seventh

offering under the

2014

ESPP began on

January 1, 2018

and ended on

June 30, 2018

and the

eight

offering began on

July 1, 2018

and ended on

December 31, 2018.

During the years ended

December 31, 2018

and

2017,

74,343

and

100,358

shares, respectively, were issued under the

2014

ESPP. The Company incurred

$0.1

million in stock-based compensation expense related to the

2014

ESPP for the years ended

December 31, 2018,

2017,

and

2016.

Note 7 - Income Taxes

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Income Tax Disclosure [Text Block]

Income Taxes

not

that the benefit of its deferred tax assets will

not

significant income tax provisions or benefits for the

nine

months ended

September 30, 2019

and

2018.

10.

Income Taxes

The components of loss from operations before income taxes are as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Domestic	$	(17,855	)	$	(24,803	)	$	(15,860	)
Foreign		(2,874	)		(5,161	)		(12,666	)
Total	$	(20,729	)	$	(29,964	)	$	(28,526	)

For the years ended

December 31, 2018,

2017,

2016,

the Company has

not

recorded a provision for federal or state income taxes as it has had net operating losses since inception.

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations is as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Income tax benefit computed at federal statutory tax rate	$	(4,348	)	$	(10,186	)	$	(9,696	)
Permanent differences		6			4			430
Stock compensation - permanent items		325			689			-
R&D credit - permanent items		-			1,751			1,437
State income taxes, net of federal benefit		(958	)		(853	)		(498	)
Tax credits		(1,466	)		(5,495	)		(4,846	)
Change in valuation allowance		5,409			(54,319	)		8,804
Foreign rate differential		602			1,752			4,304
Rate change		-			2,202			-
382 limitation		-			64,975			-
Other		430			(520	)		65
Total	$	-		$	-		$	-

The significant components of the Company's deferred tax assets are as follows (in thousands):

	Year Ended December 31,
	2018			2017			2016
Deferred tax assets:
Net operating loss carryforwards	$	6,742		$	2,651		$	37,237
Federal and state tax credits		3,122			2,244			21,223
Accrued expenses		411			399			544
Patents		132			191			360
Stock-based compensation		1,782			1,262			1,353
Other		169			202			321
Total deferred tax assets		12,358			6,949			61,038
Valuation allowance		(12,358	)		(6,949	)		(61,038	)
Net deferred assets	$	-		$	-		$	-

not

that the benefit of its deferred tax assets will

not

be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of

December 31, 2018,

2017,

and

2016.

December 22, 2017,

34%

21%.

As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities at the enacted rate. This revaluation resulted in a decrease in net deferred tax asset of

$2.2

million and a corresponding reduction in the valuation allowance against these assets. There is

impact to income tax expense. The other provisions of the Tax Cuts and Jobs Act did

not

have a material impact on the

2017

2018

consolidated financial statements.

may

require further adjustments and changes in our estimates. The Company completed the analysis of the

2017

Tax Act during the

fourth

quarter of

2018

and had

material changes to the original analysis.

Net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service (the "IRS") and

may

become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a

three

-year period in excess of

50%

as defined under Sections

382

and

383

may

further affect the limitation in future years. On

August 2, 2017,

the Company completed a financing transaction for

$22.0

million. As a result of this transaction, the company performed a study to review the application of IRC

§382

and

§383

to the Company. It was determined there was an ownership change as of the date of this financing and the Company’s NOLs generated prior to

August 2, 2017

would be fully limited. Therefore, the NOLs and credits generated prior to

August 2, 2017

have been written down to zero. This represents a decrease in Federal NOLs of approximately

$107.3

million (

$34.1

million tax effected) and a decrease in federal credits of

$23.8

million. State NOLs and credits were also fully limited as a result of this ownership change. The state NOLs were reduced by approximately

$5.0

million and credits were reduced by

$2.1

million.

As a result of current year activity, the valuation allowance increased by approximately

$5.4

million during the year ended

December 31, 2018.

This was due primarily to the addition of Orphan Drug Tax credits and the generation of net operating losses. In the year ended

December 31, 2017,

the valuation allowance had an increase of approximately

$13.1

million. However, this increase was offset by a reduction of

$65.0

million due to the aforementioned

§382

limitation and a reduction of

$2.2

million due to the change in tax rate. Therefore, there was an overall decrease to the valuation allowance

$54.1

million. The valuation allowance increased by approximately

$8.8

million during the year ended

December 31, 2016,

due primarily to the addition of Orphan Drug Tax credits and the generation of net operating losses.

Subject to the limitations described below, as of

December 31, 2018,

2017,

and

2016,

the Company has net operating loss carryforwards of approximately

$25.7

million,

$10.6

million, and

$0.0

million, respectively, to offset future federal taxable income. The pre-

2018

federal net operating loss carryforwards expire at various dates through

2037.

Federal net operating loss carryforwards generated in

2018

and forward will have an unlimited carryforward period as part of the Tax Cuts and Jobs Act. The indefinite lived net operating loss carryforwards as of

December 31, 2018

are approximately

$14.7

million. As of

December 31, 2018,

2017,

and

2016,

the Company has state net operating loss carryforwards of approximately

$21.5

million,

$6.8

million, and

$0.0

million, respectively, to offset future state taxable income, which will expire at various times between

2037

and

2038.

As of

December 31, 2018,

2017

and

2016,

the Company has tax credit carryforwards of approximately

$3.1

million,

$2.3

million and

$0.0

million, respectively, to offset future federal and state income taxes, which will expire at various times between

2037

and

2038.

The Company had

unrecognized tax benefits or related interest and penalties accrued during the years ended

December 31, 2018,

2017,

and

2016.

The Company will recognize interest and penalties related to uncertain tax positions in income tax expense.

December 31, 2015

through

2018,

although carryforward attributes that were generated prior to tax year

2015

may

still be adjusted upon examination by the IRS or state tax authorities if they either have been or will be used in a future period. Currently,

federal or state income tax returns are under examination by the respective taxing authorities.

Note 8 - Net Loss Per Share Attributable to Common Stockholders

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes to Financial Statements

Earnings Per Share [Text Block]

Net Loss per Share Attributable to Common Stockholders

As described in Note

three

and

nine

months ended

September 30, 2019

and

2018

resulted in net losses, there is

income allocation required under the

two

-class method or dilution attributed to weighted-average shares outstanding in the calculation of diluted loss per share.

The following Common Stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Outstanding stock options		772,847		4,597,226		772,847		4,597,226
Outstanding ESPP shares		-		26,642		-		26,642
Convertible preferred stock		21,771,032		22,112,775		21,771,032		22,112,775
		22,543,879		26,736,643		22,543,879		26,736,643

11.

Net Loss per Share Attributable to Common Stockholders

As described in Note

December 31, 2018,

2017

and

2016

resulted in net losses, there is

income allocation required under the

two

-class method or dilution attributed to weighted-average shares outstanding in the calculation of diluted loss per share. In

2017

the net loss applicable to Common Stock did

not

equal net loss due to the accretion of the beneficial conversion feature of Preferred Stock in the amount of

$6.7

not

have a stated redemption date and is immediately convertible at the option of the holder.

The following Common Stock equivalents, presented on an as converted basis, were excluded from the calculation of net loss per share for the periods presented, due to their anti-dilutive effect:

	Year Ended December 31,
	2018		2017		2016
Outstanding stock options		4,597,226		2,681,072		2,166,254
Convertible preferred stock		22,112,775		22,112,775		-
		26,710,001		24,793,847		2,166,254

Note 9 - Restructuring Charges

9 Months Ended

Sep. 30, 2019

Notes to Financial Statements

Restructuring and Related Activities Disclosure [Text Block]

Restructuring Charges

April 2019,

the Board of Directors approved a plan (

“2019

Restructuring Program”) to reduce operating expenses as the Company evaluates its strategic alternatives following the release of top-line data from the PATENCY-

clinical trial of vonapanitase on

March 28, 2019.

The restructuring initiatives are company-wide. The remainder of the charges are expected to be incurred by the end of the fiscal year ending

December 31, 2019 (

“Fiscal Year

2019”

). These actions are expected to result in pre-tax charges of

$2.9

million, all of which are anticipated to be cash expenditures and all of which were recorded in the

three

months ended

June 30, 2019.

Changes in the restructuring accrual during the

first

nine

months ended

September 30, 2019

are summarized below (in thousands):

	As of December 31, 2018		Charges/(Benefits)		Payment/Other			As of September 30, 2019
2019 Restructuring Program
Employee Severance	$	-	$	2,854	$	(1,834	)	$	1,020
Total	$	-	$	2,854	$	(1,834	)	$	1,020

Significant Accounting Policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation, Principles of Consolidation and Use of Estimates

December 31, 2018

and notes thereto, included in the Company’s Annual Report on Form

-K, as filed with the SEC on

March 13, 2019.

September 30, 2019,

the results of its operations for the

three

and

nine

months ended

September 30, 2019

and

2018,

results of changes in stockholders equity for the

nine

months ended

September 30, 2019

and

2018,

and its cash flows for the

nine

months ended

September 30, 2019

and

2018.

Such adjustments are of a normal and recurring nature. The results for the

three

and

nine

months ended

September 30, 2019

are

not

necessarily indicative of the results for the year ending

December 31, 2019,

or for any future period.

not

may

differ from those estimates or assumptions.

Basis of Presentation, Principles of Consolidation and Use of Estimates

not

may

differ from those estimates or assumptions.

Fair Value Measurement, Policy [Policy Text Block]

Fair Value of Financial Instruments

820,

Fair Value Measurement and Disclosures

not

a measure of the investment credit quality. Fair value measurements are classified and disclosed in

one

of the following

three

categories:

Level

1—Valuations

based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

Level

2—Valuations

based on quoted prices for similar assets or liabilities in markets that are

not

active or for which all significant inputs are observable, either directly or indirectly.

Level

3—Valuations

that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Financial instruments measured at fair value on a recurring basis include cash equivalents and available-for-sale investments. There have been

changes to the valuation methods utilized by the Company during the

three

and

nine

months ended

September 30, 2019

and

2018.

The Company evaluates transfers between levels at the end of each reporting period. There were

transfers of financial instruments between levels during the

three

and

nine

months ended

September 30, 2019

and

2018.

Segment Information

one

operating segment, which is the business of developing and commercializing vonapanitase for the treatment of renal and vascular disease. Currently, the Company operates in only

one

geographic segment.

Earnings Per Share, Policy [Policy Text Block]

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

Net Income (Loss) per Share Attributable to Common Stockholders

The Company follows the

two

-class method when computing net income (loss) per share in periods when issued shares that meet the definition of participating securities are outstanding. The

two

not

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers (“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

2016

January 1, 2019

using the optional transition method that allows for a cumulative-effect adjustment in the period of adoption and will

not

restate prior periods. It has have also elected to adopt the package of practical expedients permitted in Accounting Standards Codification Topic

842,

or ASC

842.

Accordingly, it is continuing to account for its existing operating lease as an operating lease under the new guidance, without reassessing whether the contract contains a lease under ASC

842

or whether classification of the operating leases would be different under ASC Topic

842,

and to treat lease and non-lease components as a single lease component. The Company’s sole lease at the adoption date was an operating lease for facilities and did

not

include any non-lease components.

As a result of the adoption of ASU

2016

02,

January 1, 2019,

the Company recognized (a) a lease liability of approximately

$0.2

million, which represents the present value of its remaining lease payments using an estimated incremental borrowing rate of

8%,

(b) a right-of-use asset of approximately

$0.2

million that will be expensed as operating lease expense over the term of the lease. Due to the adoption of the standard using the retrospective cumulative-effect adjustment method, there are

changes to previously reported results prior to

January 1, 2019.

Lease expense is

not

expected to change materially as a result of the adoption of ASU

2016

02.

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments (“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and the ending balances by

$22,000

for both the

nine

months ended

September 30, 2019

and

2018.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting (“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the condensed consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company adopted ASU

2018

during the quarter ended

March 31, 2019.

The adoption did

not

have an impact on the condensed consolidated financial statements as all outstanding non-employee share-based awards had vested prior to

March 31, 2018.

Recent Accounting Pronouncements

May 2014,

the FASB issued ASU

2014

09,

Revenue from Contracts with Customers

(“ASU

2014

09”

January 1, 2018,

with early adoption permitted. The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

February 2016,

the FASB issued ASU

2016

02,

Leases (Topic

842

): Amendments to FASB Codification (“ASU

2016

02”

January 1, 2019

not

August 2016,

the FASB issued ASU

2016

15,

Statement of Cash Flows (Topic

230

): Classification of Certain Cash Receipts and Cash Payments

(“ASU

2016

15”

), which provides clarification regarding how certain cash receipts and cash payments are presented and classified in the statement of cash flows. This update addresses

eight

specific cash flow issues with the objective of reducing the existing diversity in practice. This update is effective for annual and interim periods beginning after

December 15, 2017,

which required the Company to adopt these provisions in the

first

quarter of fiscal

2018

using a retrospective approach. The Company adopted ASU

2016

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

November 2016,

the FASB issued ASU

2016

18,

Statement of Cash Flows, Restricted Cash

December 15, 2017,

with early adoption permitted. The Company adopted this standard during the

first

quarter of

2018.

2016

during the quarter ended

March 31, 2018.

The inclusion of restricted cash increased the beginning balances of the unaudited consolidated statement of cash flows by

$22,000

and

$14,000

for the years ended

December 31, 2018

and

2017,

respectively. The ending balances were increased by

$22,000

for both the years ended

December 31, 2018

and

2017.

May 2017,

the FASB issued ASU

No.

2017

09,

Compensation - Stock Compensation (Topic

718

): Scope of Modification Accounting

(“ASU

2017

09”

2017

09,

an entity will

not

2017

will be applied prospectively to awards modified on or after the adoption date. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The Company adopted ASU

2017

during the quarter ended

March 31, 2018.

The adoption did

not

have a material impact on the consolidated financial statements.

June 2018,

the FASB issued ASU

No.

2018

07,

Compensation - Stock Compensation (Topic

718

): Improvements to Nonemployee Share-Based Payment Accounting (“ASU

2018

07”

). ASU

2018

is effective for fiscal years and interim periods within those fiscal years beginning after

December 15, 2018.

The guidance will be effective for the Company on

January 1, 2019.

The Company is currently evaluating the impact of the new guidance on its condensed consolidated financial statements.

Note 3 - Fair Value Measurements (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	As of September 30, 2019
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	9,101	$	-	$	-	$	9,101
Total	$	9,101	$	-	$	-	$	9,101

	As of December 31, 2018
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2018
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

	As of December 31, 2017
	Quoted Prices		Significant		Significant
	in Active		Observable		Unobservable
	Markets		Inputs		Inputs
	(Level 1)		(Level 2)		(Level 3)		Total
Assets
Cash equivalents	$	11,662	$	-	$	-	$	11,662
Government securities		20,971		-		-		20,971
Total	$	32,633	$	-	$	-	$	32,633

Available-for-sale Securities [Table Text Block]

	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
September 30, 2019
Government securities
(Due within 1 year)	$	-	$	-	$	-	$	-
	$	-	$	-	$	-	$	-

December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-	$	2,496
	$	2,496	$	-	$	-	$	2,496

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-		$	2,496
	$	2,496	$	-	$	-		$	2,496

December 31, 2017
Government securities
(Due within 1 year)	$	20,991	$	-	$	(20	)	$	20,971
	$	20,991	$	-	$	(20	)	$	20,971

Note 4 - Property and Equipment, Net (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Property, Plant and Equipment [Table Text Block]

	As of
	September 30, 2019		December 31, 2018

Computer equipment and software	$	-	$	211
Furniture, fixtures, and other		-		365
Laboratory equipment		-		514
		-		1,090
Accumulated depreciation		-		(827	)
Property and equipment, net	$	-	$	263

	As of December 31,
	2018			2017

Computer equipment and software	$	211		$	192
Furniture, fixtures, and other		365			302
Laboratory equipment		514			477
		1,090			971
Accumulated depreciation		(827	)		(712	)
Property and equipment, net	$	263		$	259

Note 6 - Stock-based Compensation (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Granted		1,182,500		$	2.66
Exercised		-
Forfeited (1)		(2,606,289	)	$	2.79
Expired (1)		(2,400,590	)	$	6.51
Outstanding at September 30, 2019		772,847		$	4.89		7.3	$	-
Exercisable at September 30, 2019		476,390		$	6.13		6.4	$	-
Vested or expected to vest at September 30, 2019 (2)		772,847		$	4.89		7.3	$	-

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value

Outstanding at December 31, 2017		2,681,072		$	7.18		6.8	$	121
Granted		2,041,600		$	2.61
Exercised		-
Forfeited		(83,433	)	$	5.82
Expired		(42,013	)	$	13.30
Outstanding at December 31, 2018		4,597,226		$	5.12		7.4	$	404
Exercisable at December 31, 2018		2,067,356		$	7.57		5.7	$	241
Vested or expected to vest at December 31, 2018 (1)		4,597,226		$	5.12		7.4	$	404

Common Stock Reserved for Future Issuance [Table Text Block]

	September 30,		December 31,
	2019		2018

Conversion of Series A Preferred Stock		21,771,032		22,112,775
Stock-based compensation awards		6,818,214		5,163,957
Employee Stock Purchase Plan		118,120		118,120
Total		28,707,366		27,394,852

	December 31,		December 31,
	2018		2017

Conversion of Series A Preferred Stock		22,112,775		22,112,775
Stock-based compensation awards		5,163,957		3,572,457
Employee Stock Purchase Plan		118,120		192,463
Total		27,394,852		25,877,695

Note 8 - Net Loss Per Share Attributable to Common Stockholders (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Outstanding stock options		772,847		4,597,226		772,847		4,597,226
Outstanding ESPP shares		-		26,642		-		26,642
Convertible preferred stock		21,771,032		22,112,775		21,771,032		22,112,775
		22,543,879		26,736,643		22,543,879		26,736,643

	Year Ended December 31,
	2018		2017		2016
Outstanding stock options		4,597,226		2,681,072		2,166,254
Convertible preferred stock		22,112,775		22,112,775		-
		26,710,001		24,793,847		2,166,254

Note 9 - Restructuring Charges (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedule of Restructuring Reserve by Type of Cost [Table Text Block]

	As of December 31, 2018		Charges/(Benefits)		Payment/Other			As of September 30, 2019
2019 Restructuring Program
Employee Severance	$	-	$	2,854	$	(1,834	)	$	1,020
Total	$	-	$	2,854	$	(1,834	)	$	1,020

Note 1 - Organization and Operations (Details Textual)		6 Months Ended
Note 1 - Organization and Operations (Details Textual)	Sep. 23, 2019 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares
Cash, Cash Equivalents, and Short-term Investments, Total			$ 9,300,000	$ 21,900,000
Retained Earnings (Accumulated Deficit), Ending Balance			$ (223,852,000)	$ (210,470,000)	$ (189,741,000)
Preferred Stock, Par or Stated Value Per Share \| $ / shares			$ 0.001	$ 0.001	$ 0.001
Merger Agreement with ArTara [Member]
Amendment of Certificate of Incorporation, Beneficial Ownership Cap	9.985%
Subscription Agreement, Minimum Commitment Amount	$ 40,000,000
Merger Consummation Conditions, Net Cash Required	0
Business Combination, Termination Fee That May Be Required of Acquirer	800,000
Business Combination, Termination Fee That May Be Required of Acquiree	800,000
Business Combination, Maximum Reimbursement of the Other Party's Expenses By Either the Acquirer or Acquiree	$ 400,000
Period of Lock-out Agreement	180 days
Number of Directors Expected Following the Merger	7
Number of Directors Expected Following the Merger, Number Designated By Acquiree	5
Number of Directors Expected Following the Merger, Number Designated By Acquirer	1
Number of Directors Expected Following the Merger, Chief Executive Officer of the Combined Company	1
Merger Agreement with ArTara [Member] \| Private Placement [Member] \| Common Stock [Member]
Subscription Agreement, Maximum Number of Shares Agreed to Issue \| shares	15,300
Merger Agreement with ArTara [Member] \| Private Placement [Member] \| Series 1 Convertible Non-voting Preferred Stock [Member]
Subscription Agreement, Maximum Number of Shares Agreed to Issue \| shares	27,200
Preferred Stock, Par or Stated Value Per Share \| $ / shares	$ 0.001
Subscription Agreement, Purchase Price of Shares Agreed to Issue, Multiple of Common Stock Purchase Price	1,000
Convertible Preferred Stock, Shares Issued upon Conversion \| shares	1,000
Preferred Stock, Liquidation Preference Per Share \| $ / shares	$ 10
Merger Agreement with ArTara [Member] \| The 2014 Plan [Member]
Amendment of Compensation Plan, Increase in Shares Available Under Equity Incentive Plan, Threshold for Common Stock Reserved for Issuance, Percentage	15.20%
Merger Agreement with ArTara [Member] \| Minimum [Member]
Amendment of Certificate of Incorporation, Reverse Stock Split to Occur, Ratio	30
Merger Agreement with ArTara [Member] \| Minimum [Member] \| Private Placement [Member] \| Series 1 Convertible Non-voting Preferred Stock [Member]
Conversion of Preferred Stock, Beneficial Ownership Threshold, Percentage	9.99%
Merger Agreement with ArTara [Member] \| Maximum [Member]
Amendment of Certificate of Incorporation, Reverse Stock Split to Occur, Ratio	50
Merger Agreement with ArTara [Member] \| Maximum [Member] \| Private Placement [Member] \| Series 1 Convertible Non-voting Preferred Stock [Member]
Conversion of Preferred Stock, Beneficial Ownership Threshold, Percentage	19.99%
Forecast [Member]
Severance Costs		$ 2,900,000

Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	$ (10,022,000)	$ (2,945,000)	$ (1,799,000)	$ (15,222,000)	$ (3,639,000)
Restricted Cash and Cash Equivalents, Total	22,000	22,000	22,000	22,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Current						$ 200,000
Operating Lease, Weighted Average Discount Rate, Percent						8.00%
Operating Lease, Right-of-Use Asset						$ 200,000
Accounting Standards Update 2016-18 [Member]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	$ 22,000	$ 22,000	$ 22,000	$ 14,000

Note 3 - Fair Value Measurements - Available-for-sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost	$ 2,496	$ 20,991
Unrealized Gains
Unrealized Losses		(20)
Fair Value	2,496	20,971
US Government Agencies Debt Securities [Member]
Amortized Cost	2,496	20,991
Unrealized Gains
Unrealized Losses		(20)
Fair Value	$ 2,496	$ 20,971

Note 3 - Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Total	$ 9,101	$ 20,849	$ 32,633
Cash Equivalents [Member]
Cash equivalents	9,101	18,353	11,662
US Government Agencies Debt Securities [Member]
Government securities		2,496	20,971
Fair Value, Inputs, Level 1 [Member]
Total	9,101	20,849	32,633
Fair Value, Inputs, Level 1 [Member] \| Cash Equivalents [Member]
Cash equivalents	9,101	18,353	11,662
Fair Value, Inputs, Level 1 [Member] \| US Government Agencies Debt Securities [Member]
Government securities		2,496	20,971
Fair Value, Inputs, Level 2 [Member]
Total
Fair Value, Inputs, Level 2 [Member] \| Cash Equivalents [Member]
Cash equivalents
Fair Value, Inputs, Level 2 [Member] \| US Government Agencies Debt Securities [Member]
Government securities
Fair Value, Inputs, Level 3 [Member]
Total
Fair Value, Inputs, Level 3 [Member] \| Cash Equivalents [Member]
Cash equivalents
Fair Value, Inputs, Level 3 [Member] \| US Government Agencies Debt Securities [Member]
Government securities

Note 4 - Property and Equipment, Net (Details Textual) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 01, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation, Total		$ 100,000	$ 22,000	$ 279,000	$ 83,000	$ 115,000	$ 148,000	$ 123,000
Property, Plant and Equipment, Net, Ending Balance		$ 0		0		$ 263,000	$ 259,000
Laboratory Equipment [Member] \| Research and Development Expense [Member]
Impairment of Long-Lived Assets Held-for-use	$ 0			$ 200,000

Note 4 - Property and Equipment, Net - Summary of Property and Equipment (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and equipment		$ 1,090,000	$ 971,000
Accumulated depreciation		(827,000)	(712,000)
Property and equipment, net	0	263,000	259,000
Computer Equipment and Software [Member]
Property and equipment		211,000	192,000
Furniture and Fixtures [Member]
Property and equipment		365,000	302,000
Laboratory Equipment [Member]
Property and equipment		$ 514,000	$ 477,000

Note 5 - Commitments and Contingencies (Details Textual) a in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Oct. 31, 2019 a	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 31, 2017 ft²
Operating Lease, Expense	$ 100,000	$ 200,000
Area of Real Estate Property \| ft²							7,500
Security Deposit				$ 22,000	$ 22,000
Letters of Credit Outstanding, Amount	22,000	22,000			22,000	$ 22,000
Loans Pledged as Collateral	$ 22,000	$ 22,000			$ 22,000	$ 22,000
Subsequent Event [Member]
Area of Real Estate Property \| a			0

Note 6 - Stock-based Compensation (Details Textual) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2019	Jan. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
Share-based Payment Arrangement, Expense			$ 96,000	$ 904,000	$ 977,000	$ 2,647,000	$ 3,429,000	$ 3,227,000	$ 3,343,000
The 2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period				0		51,984
Share-based Payment Arrangement, Expense			$ 0	$ 20,000	$ 68,000	$ 100,000
The 2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			192,436		192,436		304,991			140,500
Share-based Compensation Arrangement by Share-based Payment Award, Number of Annual Additional Shares, Percentage	1.00%						1.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Additional Shares Authorizable	281,000	281,000
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			0		0		74,343	100,358
Share-based Payment Arrangement, Expense							$ 100,000	$ 100,000	$ 100,000

Note 6 - Stock-based Compensation - Stock Option Activity for Employees and Non-employees (Details) - USD ($)
$ / shares in Units, $ in Thousands

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Options Outstanding, Beginning Balance (in shares)

4,597,226

2,681,072

Options Outstanding, Weighted Average Exercise Price, Beginning Balance (in dollars per share)

$ 5.12

$ 7.18

Options Outstanding, Weighted-average Remaining Contractual Term (Year)

7 years 109 days

7 years 146 days

6 years 292 days

Options Outstanding, Aggregate Intrinsic Value

$ 404

$ 121

Options Granted (in shares)

1,182,500

2,041,600

719,337

132,495

Options Granted, Weighted Average Exercise Price (in dollars per share)

$ 2.66

$ 2.61

$ 7.11

Options Exercised (in shares)

Options Exercised, Weighted Average Exercise Price (in dollars per share)

Options Forfeited (in shares)

(2,606,289)

^[1]

(83,433)

Options Forfeited, Weighted Average Exercise Price (in dollars per share)

$ 2.79

^[1]

$ 5.82

Options Expired (in shares)

(2,400,590)

^[1]

(42,013)

Options Expired, Weighted Average Exercise Price (in dollars per share)

$ 6.51

^[1]

$ 13.30

Options Outstanding, Ending Balance (in shares)

772,847

4,597,226

2,681,072

Options Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)

$ 4.89

$ 5.12

$ 7.18

Options Exercisable (in shares)

476,390

2,067,356

Options Exercisable, Weighted Average Exercise Price (in dollars per share)

$ 6.13

$ 7.57

Options Exercisable, Weighted-average Remaining Contractual Term (Year)

6 years 146 days

5 years 255 days

Options Exercisable, Aggregate Intrinsic Value

$ 241

Options Vested or Expected to Vest (in shares)

772,847

^[2]

4,597,226

^[3]

Options Vested or Expected to Vest, Weighted Average Exercise Price (in dollars per share)

$ 4.89

^[2]

$ 5.12

^[3]

Options Vested or Expected to Vest, Weighted-average Remaining Contractual Term (Year)

7 years 109 days

^[2]

7 years 146 days

^[3]

Options Vested or Expected to Vest, Aggregate Intrinsic Value

^[2]

$ 404

^[3]

[1]	Represents the number of options cancelled during the nine months ended September 30, 2019 as a result of employees that were terminated due to the reduction in force.
[2]	Represents the number of vested options at September 30, 2019 plus the number of unvested options expected to vest based on the unvested options outstanding at September 30, 2019."
[3]	Represents the number of vested options at December 31, 2018 plus the number of unvested options expected to vest based on the unvested options outstanding at December 31, 2018.

Note 6 - Stock-based Compensation - Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Reserved for future issuance (in shares)	28,707,366	27,394,852	25,877,695
The 2014 Employee Stock Purchase Plan [Member]
Reserved for future issuance (in shares)	118,120	118,120	192,463	140,500
Performance Shares [Member]
Reserved for future issuance (in shares)	6,818,214	5,163,957	3,572,457
Conversion of Series A Preferred Stock to Common Stock [Member]
Reserved for future issuance (in shares)	21,771,032	22,112,775	22,112,775

Note 7 - Income Taxes (Details Textual) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Total	$ 0	$ 0

Note 8 - Net Loss Per Share Attributable to Common Stockholders - Common Stock Equivalents Excluded From Calculation of Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities (in shares)	22,543,879	26,736,643	22,543,879	26,736,643	26,710,001	24,793,847	2,166,254
Convertible Preferred Stock [Member]
Antidilutive Securities (in shares)	21,771,032	22,112,775	21,771,032	22,112,775	22,112,775	22,112,775
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities (in shares)	772,847	4,597,226	772,847	4,597,226	4,597,226	2,681,072	2,166,254
Employee Stock Purchase Plan [Member]
Antidilutive Securities (in shares)		26,642		26,642

Note 9 - Restructuring Charges (Details Textual) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Restructuring Charges, Total		$ 2,854
Forecast [Member]
Restructuring Charges, Total	$ 2,900

Note 9 - Restructuring Charges - Changes in the Restructuring Accrual (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Beginning balance
Charges/(Benefits)	2,854
Payment/Other	(1,834)
Ending balance	1,020
Employee Severance [Member]
Beginning balance
Charges/(Benefits)	2,854
Payment/Other	(1,834)
Ending balance	$ 1,020