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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Aug. 12, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	Trevi Therapeutics, Inc.
Entity Central Index Key	0001563880
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Trading Symbol	TRVI
Entity Common Stock, Shares Outstanding		17,834,570
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	true
Entity File Number	001-38886
Entity Tax Identification Number	450834299
Entity Address, Address Line One	195 Church Street
Entity Address, Address Line Two	14th Floor
Entity Address, City or Town	New Haven
Entity Address, State or Province	Connecticut
Entity Address, Postal Zip Code	06510
City Area Code	203
Local Phone Number	304-2499

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 71,387	$ 7,202
Tax credit and other receivables	251	184
Prepaid expenses	2,970	1,438
Total current assets	74,608	8,824
Deferred offering costs		1,534
Operating lease right-of-use asset	350
Security deposit	19	19
Property, equipment and leasehold improvements, net	139	149
Total assets	75,116	10,526
Current liabilities:
Accounts payable	2,663	603
Accrued expenses	4,351	2,073
Operating lease liability - current portion	91
Total current liabilities	7,105	2,676
Obligation for loan success fee		460
Series C redeemable convertible preferred stock liability		1,096
Operating lease liability - long term portion	308	46
Commitments and contingencies (Note 13)
Stockholders’ equity (deficit):
Common stock: $0.001 par value; 200,000,000 and 101,929,904 shares authorized at June 30, 2019 and December 31, 2018, respectively; and 17,834,570 and 438,600 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively.	18	4
Preferred stock: $0.001 par value; 5,000,000 shares and no shares authorized at June 30, 2019 and December 31, 2018, respectively; no shares issued or outstanding at June 30, 2019 or December 31, 2018.
Additional paid-in capital	168,002
Accumulated deficit	(100,317)	(109,498)
Total stockholders’ equity (deficit)	67,703	(109,494)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	$ 75,116	10,526
Series A Redeemable convertible Preferred Stock [Member]
Current liabilities:
Temporary Equity, Carrying Amount, Attributable to Parent		21,033
Stockholders’ equity (deficit):
Total stockholders’ equity (deficit)		21,033
Series B Redeemable convertible Preferred Stock [Member]
Current liabilities:
Temporary Equity, Carrying Amount, Attributable to Parent		33,686
Stockholders’ equity (deficit):
Total stockholders’ equity (deficit)		33,686
Series C Redeemable convertible Preferred Stock [Member]
Current liabilities:
Temporary Equity, Carrying Amount, Attributable to Parent		61,023
Stockholders’ equity (deficit):
Total stockholders’ equity (deficit)		$ 61,023

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	200,000,000	101,929,904
Common Stock, Shares, Issued	17,834,570	438,600
Common Stock, Shares, Outstanding	17,834,570	438,600
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	5,000,000	0
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Series A Redeemable convertible Preferred Stock [Member]
Temporary Equity, Shares Authorized	0	15,387,923
Temporary Equity, Shares Issued	0	15,387,923
Temporary Equity, Shares Outstanding	0	15,387,923
Temporary Equity, Liquidation Preference	$ 0	$ 20,469
Preferred Stock, Shares Authorized		15,387,923
Preferred Stock, Shares Issued		15,387,923
Preferred Stock, Shares Outstanding		15,387,923
Series B Redeemable convertible Preferred Stock [Member]
Temporary Equity, Shares Authorized	0	22,608,695
Temporary Equity, Shares Issued	0	22,608,695
Temporary Equity, Shares Outstanding	0	22,608,695
Temporary Equity, Liquidation Preference	$ 0	$ 32,900
Series C Redeemable convertible Preferred Stock [Member]
Temporary Equity, Shares Authorized	0	48,200,412
Temporary Equity, Shares Issued	0	38,097,672
Temporary Equity, Shares Outstanding	0	38,097,672
Temporary Equity, Liquidation Preference	$ 0	$ 59,798

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating expenses:
Research and development	$ 5,528	$ 3,439	$ 8,866	$ 5,802
General and administrative	1,889	941	3,363	1,720
Total operating expenses	7,417	4,380	12,229	7,522
Loss from operations	(7,417)	(4,380)	(12,229)	(7,522)
Other income (expense):
Change in fair value of Series C redeemable convertible preferred stock liability		(422)		(1,266)
Change in fair value of obligation for loan success fee	(163)	(68)	(215)	(80)
Interest income	229	38	287	83
Interest expense		(51)		(174)
Total other income (expense), net	66	(503)	72	(1,437)
Loss before income tax benefit	(7,351)	(4,883)	(12,157)	(8,959)
Income tax benefit	5	25	9	50
Net loss	(7,346)	(4,858)	(12,148)	(8,909)
Accretion of redeemable convertible preferred stock	1,332	175	1,535	370
Dividends accrued on redeemable convertible preferred stock	(686)	(1,293)	(2,239)	(2,573)
Adjusted net loss attributable to common stockholders	$ (6,700)	$ (5,976)	$ (12,852)	$ (11,112)
Basic and diluted net loss per common share outstanding	$ (0.63)	$ (13.62)	$ (2.32)	$ (25.45)
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted	10,571,736	438,606	5,535,907	436,598

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Initial Public Offering [Member]	Private Placement [Member]	Common Stock [Member]	Common Stock [Member] Initial Public Offering [Member]	Common Stock [Member] Private Placement [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Initial Public Offering [Member]	Additional Paid-in Capital [Member] Private Placement [Member]	Retained Earnings [Member]	Series A Redeemable convertible Preferred Stock [Member]	Series B Redeemable convertible Preferred Stock [Member]	Series C Redeemable convertible Preferred Stock [Member]
Beginning Balance at Dec. 31, 2017	$ (84,428)			$ 4						$ (84,432)	$ 20,479	$ 32,640	$ 46,087
Beginning Balance (in shares) at Dec. 31, 2017				432,921							15,387,923	22,608,695	30,886,507
Stock-based compensation	190						$ 190
Issuance of common stock from exercise of stock options	13						13
Issuance of common stock from exercise of stock options (in shares)				5,679
Dividends accrued on redeemable convertible preferred stock	(2,573)						(203)			(2,370)	$ 458	$ 774	$ 1,341
Accretion (amortization) of premium (discount) on issuance of redeemable convertible preferred stock	(8)									(8)	(2)	10
Accretion of discount on investor rights/obligation	(65)									(65)	27	38
Adjustment for excess (shortfall) of fair value over liquidation value of redeemable convertible preferred stock	498									498	(212)	(306)	20
Accretion of issuance costs on redeemable convertible preferred stock	(55)									(55)	2	1	52
Net loss	(8,909)									(8,909)
Ending Balance at Jun. 30, 2018	(95,337)			$ 4						(95,341)	$ 20,752	$ 33,157	$ 47,500
Ending Balance (in shares) at Jun. 30, 2018				438,600							15,387,923	22,608,695	30,886,507
Beginning Balance at Dec. 31, 2017	(84,428)			$ 4						(84,432)	$ 20,479	$ 32,640	$ 46,087
Beginning Balance (in shares) at Dec. 31, 2017				432,921							15,387,923	22,608,695	30,886,507
Net loss	(20,500)
Ending Balance at Dec. 31, 2018	(109,494)			$ 4						(109,498)	$ 21,033	$ 33,686	$ 61,023
Ending Balance (in shares) at Dec. 31, 2018				438,600							15,387,923	22,608,695	38,097,672
Beginning Balance at Mar. 31, 2018	(89,463)			$ 4						(89,467)	$ 20,615	$ 32,897	$ 46,779
Beginning Balance (in shares) at Mar. 31, 2018				438,600							15,387,923	22,608,695	30,886,507
Stock-based compensation	102						102
Dividends accrued on redeemable convertible preferred stock	(1,293)						(102)			(1,191)	$ 230	$ 388	$ 675
Accretion (amortization) of premium (discount) on issuance of redeemable convertible preferred stock	(4)									(4)	(1)	5
Accretion of discount on investor rights/obligation	(32)									(32)	13	19
Adjustment for excess (shortfall) of fair value over liquidation value of redeemable convertible preferred stock	239									239	(106)	(153)	20
Accretion of issuance costs on redeemable convertible preferred stock	(28)									(28)	1	1	26
Net loss	(4,858)									(4,858)
Ending Balance at Jun. 30, 2018	(95,337)			$ 4						(95,341)	$ 20,752	$ 33,157	$ 47,500
Ending Balance (in shares) at Jun. 30, 2018				438,600							15,387,923	22,608,695	30,886,507
Beginning Balance at Dec. 31, 2018	(109,494)			$ 4						(109,498)	$ 21,033	$ 33,686	$ 61,023
Beginning Balance (in shares) at Dec. 31, 2018				438,600							15,387,923	22,608,695	38,097,672
Stock-based compensation	383						383
Issuance of common stock from exercise of stock options	$ 38						38
Issuance of common stock from exercise of stock options (in shares)	14,736			14,736
Issuance of Series C redeemable convertible preferred stock, net of issuance costs													$ 11,059
Issuance of Series C redeemable convertible preferred stock, net of issuance costs (in shares)													6,849,315
Dividends accrued on redeemable convertible preferred stock	$ (2,239)									(2,239)	$ 326	$ 551	$ 1,362
Dividends accrued on redeemable convertible preferred stock, (in shares)											5,406,844	6,478,999	3,792,386
Accretion (amortization) of premium (discount) on issuance of redeemable convertible preferred stock	(24)									(24)	$ (7)	$ 31
Accretion of discount on investor rights/obligation	(201)									(201)	84	117
Adjustment for excess (shortfall) of fair value over liquidation value of redeemable convertible preferred stock	1,994									1,994	(651)	(940)	$ (403)
Accretion of issuance costs on redeemable convertible preferred stock	(234)									(234)	7	4	223
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering	127,504			$ 7			105,464			22,033	$ (20,792)	$ (33,449)	$ (73,264)
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering, (in shares)				10,381,234							(20,794,767)	(29,087,694)	(48,739,373)
Issuance of common stock value, net of underwriting discounts and commissions and issuance costs		$ 48,174	$ 13,950		$ 5	$ 2		$ 48,169	$ 13,948
Issuance of common stock shares, net of underwriting discounts and commissions and issuance costs					5,500,000	1,500,000
Net loss	(12,148)									(12,148)
Ending Balance at Jun. 30, 2019	67,703			$ 18			168,002			(100,317)
Ending Balance (in shares) at Jun. 30, 2019				17,834,570
Beginning Balance at Mar. 31, 2019	(115,476)			$ 4						(115,480)	$ 21,169	$ 33,943	$ 73,039
Beginning Balance (in shares) at Mar. 31, 2019				446,494							15,387,923	22,608,695	44,946,987
Stock-based compensation	237						237
Issuance of common stock from exercise of stock options	14						14
Issuance of common stock from exercise of stock options (in shares)				6,842
Dividends accrued on redeemable convertible preferred stock	(686)									(686)	$ 99	$ 166	$ 421
Dividends accrued on redeemable convertible preferred stock, (in shares)											5,406,844	6,478,999	3,792,386
Accretion (amortization) of premium (discount) on issuance of redeemable convertible preferred stock	(19)									(19)	$ (7)	$ 26
Accretion of discount on investor rights/obligation	(168)									(168)	70	98
Adjustment for excess (shortfall) of fair value over liquidation value of redeemable convertible preferred stock	1,716									1,716	(545)	(787)	$ (384)
Accretion of issuance costs on redeemable convertible preferred stock	(197)									(197)	6	3	188
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering	127,504			$ 7			105,634			21,863	$ (20,792)	$ (33,449)	$ (73,264)
Conversion of redeemable convertible preferred stock to common stock in connection with initial public offering, (in shares)				10,381,234							(20,794,767)	(29,087,694)	(48,739,373)
Issuance of common stock value, net of underwriting discounts and commissions and issuance costs		$ 48,174	$ 13,950		$ 5	$ 2		$ 48,169	$ 13,948
Issuance of common stock shares, net of underwriting discounts and commissions and issuance costs					5,500,000	1,500,000
Net loss	(7,346)									(7,346)
Ending Balance at Jun. 30, 2019	$ 67,703			$ 18			$ 168,002			$ (100,317)
Ending Balance (in shares) at Jun. 30, 2019				17,834,570

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (12,148)	$ (8,909)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	19	6
Changes in fair value of Series C redeemable convertible preferred stock liability		1,266
Changes in fair value of obligation for loan success fee	215	80
Accretion/accrual of term loan discounts and debt issuance costs		60
Stock-based compensation	383	190
Changes in operating assets and liabilities:
Receivables	(67)	(38)
Prepaid expenses	(1,532)	(1,559)
Accounts payable	1,714	180
Accrued expenses	2,259	(852)
Security deposit		12
Net cash used in operating activities	(9,157)	(9,564)
Investing activities
Acquisitions of property, equipment and leasehold improvements	(9)	(67)
Net cash used in investing activities	(9)	(67)
Financing activities
Repayments of term loan		(4,812)
Payment of final fees on term loan		(532)
Payment of loan success fee	(675)
Proceeds from exercises of stock options	38	13
Proceeds from sale of Series C redeemable convertible preferred stock, net of issuance costs	9,963
Proceeds from issuance of common shares upon completion of initial public offering, net of underwriting commissions and discounts	51,150
Payments of initial public offering costs	(1,075)
Proceeds from private placement, net of private placement agent fees	13,950
Net cash provided by (used in) financing activities	73,351	(5,331)
Net cash increase (decrease)	64,185	(14,962)
Cash and cash equivalents at beginning of period	7,202	22,020
Cash and cash equivalents at end of period	71,387	7,058
Supplemental disclosure of cash flow information
Interest paid		152
State research tax credits exchanged for cash		8
Supplemental disclosure of non-cash financing activities
Initial public offering costs included in accounts payable and accrued expenses	597
Dividends accrued on redeemable convertible preferred stock	2,239	2,573
Accretion on redeemable convertible preferred stock	$ (1,535)	$ (370)

Nature of the Business

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of the Business

1.	Nature of the Business

Trevi Therapeutics, Inc. (“Trevi” or the “Company”) is a clinical-stage biopharmaceutical company focused on the development and commercialization of nalbuphine ER to treat serious neurologically mediated conditions. The Company is currently developing nalbuphine ER for the treatment of chronic pruritus, chronic cough in patients with idiopathic pulmonary fibrosis (“IPF”), and levodopa-induced dyskinesia (“LID”) in patients with Parkinson’s disease. These conditions share a common pathophysiology that is mediated through opioid receptors in the central and peripheral nervous systems. Due to nalbuphine’s mechanism of action as a modulator of opioid receptors, the Company believes nalbuphine ER has the potential to be effective in treating each of these conditions.

Nalbuphine ER is an oral extended release formulation of nalbuphine. Nalbuphine is a mixed κ-opioid receptor agonist and μ-opioid receptor antagonist that has been approved and marketed as an injectable for pain indications for more than 20 years in both the United States and Europe. The κ- and μ-opioid receptors are known to be critical mediators of itch, cough and certain movement disorders. Nalbuphine’s mechanism of action also mitigates the risk of abuse associated with μ-opioid agonists because it antagonizes, or blocks, the μ-opioid receptor. Nalbuphine is currently the only opioid approved for marketing that is not classified as a controlled substance in the United States and most of Europe.

On April 22, 2019, the Company filed an amendment to the Company’s amended and restated certificate of incorporation to effect a one-for 9.5 reverse stock split of the Company’s common stock, which resulted in a proportional adjustment to the existing conversion ratios for each series of the Company’s redeemable convertible preferred stock. Accordingly, all share and per share amounts in the condensed consolidated financial statements have been retrospectively adjusted, where applicable, to reflect the effect of the reverse stock split and adjustments of the redeemable convertible preferred stock conversion for all periods presented.

On May 9, 2019, the Company completed its initial public offering (“IPO”) and a concurrent private placement in which it issued and sold an aggregate of 7,000,000 shares of common stock at an offering price of $10.00 per share, for net proceeds of $62.1 million, after deducting aggregate underwriting discounts and commissions and private placement agent fees of $4.9 million and other offering expenses of $3.0 million. The Company’s common stock began trading on The Nasdaq Global Market on May 7, 2019 under the ticker symbol “TRVI”.

Upon the closing of the IPO, the Company’s outstanding redeemable convertible preferred stock, including the accrued dividends theron, automatically converted into shares of the Company’s common stock. Upon such conversion of the redeemable convertible preferred stock, the Company reclassified the carrying values of the redeemable convertible preferred stock to common stock and additional paid-in capital.

The accompanying financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has financed its operations primarily through private placements of its redeemable convertible preferred stock and convertible notes as well as borrowings under a term loan facility, and most recently, with proceeds from the IPO and concurrent private placement completed in May 2019. The Company has incurred recurring losses since inception, including net losses attributable to the Company of $12.1 million for the six months ended June 30, 2019 and $20.5 million for the year ended December 31, 2018. In addition, as of June 30, 2019, the Company had an accumulated deficit of $100.3 million. The Company expects to continue to generate operating losses for the foreseeable future. As of August 12, 2019, the issuance date of these Condensed Consolidated Financial Statements, the Company expects that its cash and cash equivalents of $71.4 million as of June 30, 2019, will be sufficient to fund its operating expenses and capital expenditure requirements through at least 12 months from the date of issuance of these Condensed Consolidated Financial Statements.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited interim condensed consolidated financial statements for the three and six months ended June 30, 2019 and 2018 included herein, have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim information. Certain information and footnote disclosure typically prepared in accordance with GAAP have been condensed or omitted pursuant to SEC rules and regulations. The accompanying unaudited condensed consolidated financial statements and notes should be read in conjunction with the audited consolidated financial statements and related notes for the year ended December 31, 2018 included in the final prospectus for the IPO filed with the SEC on May 8, 2019. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments, which include normal recurring adjustments necessary for the fair presentation of the Company’s interim financial statements presented. The results of operations for the interim periods are not necessarily indicative of the results expected for the full year or any subsequent period.

The accompanying Condensed Consolidated Financial Statements include the accounts of Trevi Therapeutics, Inc. and its wholly-owned subsidiary Trevi Therapeutics Limited. Intercompany balances and transactions have been eliminated.

All amounts presented are in thousands of dollars, except share and per share amounts, unless noted otherwise. The Company has evaluated events occurring subsequent to June 30, 2019 for potential recognition or disclosure in the Condensed Consolidated Financial Statements and concluded there were no subsequent events that required recognition or disclosure other than those provided.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of the expenses during the reporting periods. Significant estimates and assumptions reflected in these Condensed Consolidated Financial Statements include, but are not limited to the recognition of research and development (“R&D”) expenses and the valuation of redeemable convertible preferred stock, common stock and stock-based awards. On an ongoing basis, management evaluates its estimates in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.

Unaudited Interim Financial Information

The accompanying interim Condensed Consolidated Balance Sheet as of June 30, 2019, the Condensed Consolidated Statements of Operations and the Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) for the three and six months ended June 30, 2019 and 2018, and the Condensed Consolidated Statements of Cash Flows for the six months ended June 30, 2019 and 2018 are unaudited. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the Company’s opinion, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statements of its financial position as of June 30, 2019 and the results of its operations for the three and six months ended June 30, 2019 and 2018, and its cash flows for the six months ended June 30, 2019 and 2018. The results for the three and six months ended June 30, 2019 and 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2019, any other interim period, or any future year or period.

Fair Value Measurements

The Company’s financial instruments consist of cash and cash equivalents, tax credit and other receivables, accounts payable, accrued expenses, Series C redeemable convertible preferred stock liability and obligation for loan success fee (Note 6 and Note 8). Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. The carrying amounts of cash and cash equivalents, tax credit and other receivables, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of the short term nature of those instruments. The fair value of the obligation for loan success fee was estimated utilizing a probability-weighted income approach, including variables for the timing of the success event and other probability estimates. The fair value of Series C redeemable convertible preferred stock liability at December 31, 2018 has been estimated as the excess, if any, of the fair value of the Company’s Series C redeemable convertible preferred stock (“Series C Preferred Stock”) over the purchase price of any outstanding tranches that may be sold pursuant to the Series C Preferred Stock purchase agreement (the “Series C Purchase Agreement”).

Current accounting guidance defines fair value, establishes a framework for measuring fair value in accordance with Accounting Standards Codification (“ASC”) 820, Fair Value Measurements and Disclosures, and requires certain disclosures about fair value measurements. The valuation techniques included in the guidance are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect market assumptions and are classified into the following fair value hierarchy:

Level 1—Observable inputs—quoted prices in active markets for identical assets and liabilities.

Level 2—Observable inputs other than the quoted prices in active markets for identical assets and liabilities—such as quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets, or other inputs that are observable or can be corroborated by observable market data.

Level 3—Unobservable inputs—includes amounts derived from valuation models where one or more significant inputs are unobservable and require the company to develop relevant assumptions.

The following table summarizes the financial liabilities measured at fair value on a recurring basis as of December 31, 2018, and the basis for that measurement, by level within the fair value hierarchy (Note 6 and Note 8). There were no such financial liabilities as of June 30, 2019:

	Balance December 31, 2018		Level 1		Level 2		Level 3
Financial liabilities
Series C redeemable convertible preferred stock liability	$	1,096	$	—	$	—	$	1,096
Obligation for loan success fee		460		—		—		460
	$	1,556	$	—	$	—	$	1,556

The following table represents a roll-forward of the fair value of Level 3 instruments (significant unobservable inputs):

	June 30,			December 31,
	2019			2018
Financial liabilities
Balance at beginning of year⁽¹⁾	$	1,556		$	322
Unrealized loss on Series C redeemable convertible preferred stock liability		—			2,105
Unrealized loss on obligation for loan success fee		215			138
Net settlements⁽²⁾		(1,771	)		(1,009	)
Ending balance	$	—		$	1,556

(1)	The balance at January 1, 2018 relates to the obligation for the loan success fee.

(2)

The net settlements in the six months ended June 30, 2019 relate to the $1,096 fair value of the Series C redeemable convertible preferred stock liability at the time of the third tranche of the Series C Preferred Stock financing in January 2019 and the payment of the $675 obligation for the loan success fee in May 2019. The net settlements in 2018 relate to the $1,009 fair value of the Series C redeemable convertible preferred stock liability at the time the second tranche of Series C redeemable convertible preferred stock shares was issued.

Deferred Offering Costs

The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should the planned equity financing no longer be considered probable of being consummated, the deferred offering costs are expensed immediately as a charge to operating expenses. Deferred offering costs capitalized as of December 31, 2018 were $1,534. The Company’s IPO was completed in May 2019 and these costs, as well as additional IPO costs incurred in 2019, were recorded as a reduction to stockholders’ equity. As a result, as of June 30, 2019, the Company did not have any deferred offering costs.

Basic and Diluted Net Income (Loss) per Common Share

Basic and diluted net loss per common share outstanding is determined by dividing net loss, as adjusted for accretion and accrued dividends on redeemable convertible preferred stock, by the weighted average common shares outstanding during the period. For all periods presented, outstanding shares of Series A redeemable convertible preferred stock (“Series A Preferred Stock”), shares of Series B redeemable convertible preferred stock (“Series B Preferred Stock”), shares of Series C redeemable convertible preferred stock (“Series C Preferred Stock”), if any, and shares issuable upon exercise of stock options have been excluded from the calculation because their effects would be anti-dilutive. Therefore, the weighted average common shares used to calculate both basic and diluted net loss per share are the same for all periods presented.

Recently Adopted Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02 titled Leases (“ASU 2016-02”), which requires rights and obligations arising from both operating and capital leases to be reported on the Consolidated Balance Sheet, and to disclose quantitative and qualitative information about lease transactions (such as information about variable lease payments and options to renew and terminate leases). ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, with early adoption permitted.

The Company adopted this new guidance as of January 1, 2019, which included an assessment of the impact of the new guidance on the Condensed Consolidated Financial Statements. The Company utilized the transition practical expedient added by the FASB, which eliminated the requirement that entities apply the new lease standard to the comparative periods presented in the year of adoption. The Company elected to use the package of practical expedients that allowed the Company to not reassess: (1) whether any expired or existing contracts were or contained leases, (2) lease classification for any expired or existing leases and (3) initial direct costs for any expired or existing leases. The Company additionally used the practical expedient that allows lessees to treat the lease and non-lease components of leases as a single lease component. The adoption of this standard resulted in the recognition of a right-of-use asset of $379 and related lease liabilities of $424 related to the Company’s operating lease commitments on the Condensed Consolidated Balance Sheet as of January 1, 2019 (Note 4). The impact of adoption of the new leasing standard did not have a material impact on the Condensed Consolidated Statement of Operations during the three and six months ended June 30, 2019.

Recently Issued Accounting Pronouncements

There have been no new accounting pronouncements during the three and six months ended June 30, 2019, as compared to the recent accounting pronouncements described in Note 2 to the Company’s audited consolidated financial statements for the year ended December 31, 2018 included in the final prospectus for the IPO, which could be expected to materially impact the Company’s unaudited Condensed Consolidated Financial Statements.

Prepaid Expenses

6 Months Ended

Jun. 30, 2019

Prepaid Expense Current [Abstract]

Prepaid Expenses

3.	Prepaid Expenses

Prepaid expenses consist of the following:

	As of June 30, 2019		As of December 31, 2018
Prepaid R&D payments	$	1,765	$	1,337
Prepaid corporate insurance		1,178		59
Other		27		42
	$	2,970	$	1,438

Leases

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Leases

Effective March 1, 2013, the Company entered into a lease for office space in New Haven, CT and commencing March 1, 2018, the Company entered into the First Amendment to the lease. The leased space approximates 5,600 square feet and the lease has a term of 60 months. The lease requires monthly payments ranging from approximately $10 to $11 through February 1, 2023 and provides for two designated months of free rent. The Company has the option to terminate the lease after 36 months by providing six months notice along with a payment to the landlord in an amount representing the unamortized cost of tenant improvements plus the unamortized broker’s commission, both of which had been paid by the landlord, and as defined in the agreement.

Under ASC 842, the Company determines if an arrangement is a lease at its inception. If an operating lease has a term greater than one year, the lease is recognized in the balance sheet as a right-of-use asset and an operating lease liability at lease commencement. The Company elected the short-term lease practical expedient; therefore, if an operating lease has a term less than one year, the Company will not recognize the lease on its balance sheet. The operating right-of-use asset represents the Company’s right of use to an underlying asset for the term of the lease, and the operating liability represents the Company’s obligation to make lease payments arising from the lease.

Operating lease right-of-use assets and operating lease liabilities are determined and recognized on the commencement date of the lease based on the present value of lease payments over the term of the lease. As the Company’s leases do not provide an implicit rate within the lease, the Company uses its incremental borrowing rate, which is updated periodically, based on information available at the commencement date of the lease to determine the present value of the lease payments. As of June 30, 2019, the incremental borrowing rate used on existing leases was 13.0%. The right-of-use asset also includes any lease payments related to initial direct costs and prepayments, and excludes lease incentives. Lease expense is recognized on a straight line basis over the lease term. The Company had no new leases during the six months ended June 30, 2019.

The Company’s operating leases consist of real estate and equipment, and have remaining terms ranging from approximately 1 to 4 years. The Company has no financing leases. The following table summarizes the Company’s operating leases as presented on its Condensed Consolidated Balance Sheet as of June 30, 2019:

Assets:
Operating lease right-of-use asset	$	350
Liabilities:
Operating lease liabilities, current portion		91
Operating lease liabilities, long term portion		308
Total operating lease liabilities	$	399

Future minimum lease payments under the operating leases are as follows as of June 30, 2019:

2019	$	68
2020		138
2021		138
2022		131
2023		24
Total lease payments		499
Less: imputed discount rate		(100	)
Carrying value of operating lease liabilities	$	399

Lease expense under operating leases, including leases of office equipment, was $31 and $34 for the three months ended June 30, 2019 and 2018, respectively, and $62 and $54 for the six months ended June 30, 2019 and 2018, respectively. Lease payments made in the three months ended June 30, 2019 and 2018 were $23 and $30, respectively, and $57 and $56 in the six months ended June 30, 2019 and 2018, respectively, with such amounts reflected in the Condensed Consolidated Statement of Cash Flows in operating activities.

Accrued Expenses

6 Months Ended

Jun. 30, 2019

Payables And Accruals [Abstract]

Accrued Expenses

5.	Accrued Expenses

Accrued expenses consist of the following:

	As of June 30, 2019		As of December 31, 2018
Accrued research projects	$	3,044	$	942
Accrued professional fees		561		477
Accrued compensation and benefits		602		584
Other		144		70
	$	4,351	$	2,073

Term Loan Payable

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Term Loan Payable

6.	Term Loan Payable

On December 29, 2014, the Company entered into a loan and security agreement (the “Loan Agreement”) with Solar Capital, Ltd. (“Solar”) and Square 1 Bank (“Square 1”), together (the “Lenders”), which provided $15.0 million in debt financing (the “Term Loan”). On June 29, 2018, the maturity date of the Loan Agreement, the Company made its final payments of principal and interest due to the Lenders in connection with the Term Loan, as well as $450 in full payment of the final fee and $82 in full payment of the amendment fee. As a result, there were no outstanding borrowings under the Term Loan as of June 30, 2019 or December 31, 2018, and the Company’s obligations to the Lenders under the Loan Agreement, other than the obligations under the Success Fee Agreement as described below, were terminated.

Under the terms of the Loan Agreement, the Company was obligated to pay the Lenders a Success Fee (“Success Fee”) under a Success Fee Agreement (“Success Fee Agreement”) upon the first occurrence of an Exit Event, as defined. The Exit Event included, among other things, the completion of a public offering of common stock. The amount of the Success Fee was equal to 4.5% of the $15.0 million Term Loan funded. The Success Fee Agreement was scheduled to terminate on the earlier to occur of (a) payment in full of the Success Fee pursuant to its terms, or (b) December 29, 2021. The completion of the IPO on May 9, 2019 (see Note 1) triggered the Success Fee payment obligation and the Company made payments to its Lenders totaling $675 in May 2019. Upon such payments, the Success Fee Agreement terminated.

The Success Fee Agreement represented a free-standing financial instrument. Accordingly, the Company accounted for the Success Fee provision as a derivative under ASC 815, Derivatives and Hedging, and therefore recorded an obligation for the Success Fee at its fair value on the closing date of each advance under the Loan Agreement. Upon recording such obligations for the Success Fee, the Company also recorded an offsetting loan discount, which was accreted to interest expense in the Company’s Statements of Operations through the Term Loan’s maturity date. The Company adjusted these liabilities for the Success Fee to fair value at each reporting date they remained outstanding. As discussed above, the Success Fee was paid in May 2019; and therefore, the total fair value of the Success Fee liabilities was $0 at June 30, 2019. The total fair value of these liabilities was determined to be $460 at December 31, 2018. The Company recorded non-cash charges in the amount of $163 and $68 for the three months ended June 30, 2019 and 2018, respectively, and $215 and $80 for the six months ended June 30, 2019 and 2018, respectively, representing the changes in the fair value of these liabilities since their last measurement date. The non-cash charges are included in other income (expense) in the Company’s Condensed Consolidated Statements of Operations. The obligation for the Success Fee is presented as a non-current liability in the Company’s Condensed Consolidated Balance Sheet as of December 31, 2018.

The fair values of the obligation for the Success Fee were estimated utilizing a probability-weighted income approach, including variables for the timing of the success event and other probability estimates. For the fair value calculations at December 31, 2018, significant inputs included the Success Fee rate of 4.5% of the Term Loan funded; a discount rate of 13.0%; weighted estimated time to Exit Event ranging from 0.4 to 3.1 years and probability estimates of several potential Exit Events ranging from 5.0% to 40.0%.

Interest expense on the Term Loan, comprised of interest payments, amortization of financing costs, accrual of final and amendment fees, and accretion of the Success Fee are shown below for the three and six months ended June 30, 2018. There was no such interest expense on the Term Loan for the three and six months ended June 30, 2019.

	Three Months Ended June 30,		Six Months Ended June 30,
	2018		2018
Interest payments	$	34	$	114
Amortization of financing costs		5		19
Accrual of final and amendment fees		7		24
Accretion of the Success Fee		5		17
	$	51	$	174

Common Stock

6 Months Ended

Jun. 30, 2019

Common Stock Number Of Shares Par Value And Other Disclosures [Abstract]

Common Stock

7.	Common Stock

As of June 30, 2019 and December 31, 2018, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 200,000,000 shares and 101,929,904 shares of common stock, respectively, with a par value of $0.001 per share.

As of June 30, 2019, the Company had reserved 2,778,812 shares of common stock for the exercise of outstanding stock options and the number of shares of common stock remaining available for future stock-based awards under the Company’s 2012 Stock Incentive Plan, 2019 Stock Incentive Plan and 2019 Employee Stock Purchase Plan, as shown in the table below. As of December 31, 2018, the Company had reserved 10,690,261 shares of common stock for the conversion of outstanding shares of redeemable convertible preferred stock and accrued dividends thereon, the exercise of outstanding stock options, and the number of shares of common stock remaining available for future stock-based awards under the Company’s 2012 Stock Incentive Plan as shown below (Note 9):

	June 30, 2019		December 31, 2018
Shares of common stock reserved for conversion of Series A preferred stock outstanding		—		2,154,572
Shares of common stock reserved for conversion of Series B preferred stock outstanding		—		3,011,392
Shares of common stock reserved for conversion of Series C preferred stock outstanding		—		4,311,279
Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan		1,044,759		1,213,018
Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan		1,578,947		—
Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan		155,106		—
		2,778,812		10,690,261

Redeemable Convertible Preferred Stock

6 Months Ended

Jun. 30, 2019

Disclosure Of Redeemable Convertible Preferred Stock [Abstract]

Redeemable Convertible Preferred Stock

8.	Redeemable Convertible Preferred Stock

As of June 30, 2019 and December 31, 2018, under the Company’s certificate of incorporation, the authorized number of shares of redeemable convertible preferred stock was 0 and 86,197,030, respectively. See Note 1 with respect to the Company’s IPO and the conversion of its outstanding redeemable convertible preferred stock into shares of its common stock.

As of June 30, 2019 and December 31, 2018, under the Company’s restated certificate of incorporation effective May 9, 2019, the authorized number of shares of preferred stock was 5,000,000 and 0, respectively.

Prior to the conversion into common stock as noted above, the Company’s redeemable convertible preferred stock was redeemable on or after July 14, 2020 and carried a cumulative coupon dividend rate of 6%. The redemption amount per share for a share of redeemable convertible preferred stock was the greater of (A) the applicable original issue price per share for such series of redeemable convertible preferred stock, plus any of the dividends accrued but unpaid thereon, whether or not declared, together with any other dividends declared but unpaid thereon, and (B) the fair market value per share of redeemable convertible preferred stock, as described below under Redemption Rights. The Company accounted for its redeemable convertible preferred stock under the requirements of ASC 480, which establishes standards for how an issuer classifies and measures certain financial instruments with characteristics of both liabilities and equity. The carrying value of the redeemable convertible preferred stock was presented as temporary equity and was adjusted by periodic accretions so that the carrying amount equaled the redemption amount at the estimated date that the redeemable convertible preferred stock would be redeemed. These adjustments were effected through charges against additional paid-in capital, to the extent it was available, or accumulated deficit. For all issuances of redeemable convertible preferred stock, the difference between the amount invested by the holders of the redeemable convertible preferred stock, net of issuance costs and premiums (or discounts), as compared to the redemption value, was recorded as accretion over the redemption period of the redeemable convertible preferred stock. The accretion was added to net loss to arrive at the net loss available to common stockholders in the calculation of net loss per common share.

Issuance of Series A Redeemable Convertible Preferred Stock

On December 4, 2012, the Company entered into the Series A Preferred Stock Purchase Agreement (the “Series A Purchase Agreement”) with TPG Biotechnology Partners III, L.P. (“TPG”) and nine other holders of the Company’s convertible notes that were issued in 2011 and 2012 (the “Series A Investors”). Pursuant to the Series A Purchase Agreement, the Company issued 6,000,000 shares (the “Series A Initial Closing”) of Series A Preferred Stock to TPG at a purchase price of $1.00 per share, resulting in proceeds, net of $128 in issuance costs, of $5.9 million (the “Series A Financing”). Concurrently, convertible notes held by the Series A Investors totaling $564, including accrued interest, were automatically converted at a conversion price of $0.467 per share in accordance with calculations specified in the applicable note purchase agreement, and the Company issued 1,207,923 shares of Series A Preferred Stock in settlement of the convertible notes.

The Series A Purchase Agreement also provided for the sale of 4,000,000 additional shares of Series A Preferred Stock (the “Series A Milestone Shares”) to TPG at a purchase price of $1.00 per share upon the Company’s achievement of specified Milestone Events, as defined in the Series A Purchase Agreement, involving the Company’s Phase 1b clinical trial in uremic pruritus and a pending patent application. In the event the Milestone Events were not achieved, TPG had the right to purchase the Series A Milestone Shares, in full or in part, under the same terms and conditions as the Series A Initial Closing, including the $1.00 per share purchase price, on or before June 30, 2014.

In addition, TPG had the right to purchase, under the same terms and conditions as the Series A Initial Closing, including the $1.00 per share purchase price, the lesser of 2,500,000 additional shares of Series A Preferred Stock (the “Additional Series A Preferred Shares”) and the number of shares of Series A Preferred Stock equal to 25% of the total number of shares of Series A Preferred Stock it previously purchased for cash under the Series A Purchase Agreement. This additional right was exercisable until the date six months after the completion date of the Company’s Phase 2b/3 clinical trial of nalbuphine ER in patients with uremic pruritus.

On December 26, 2013, TPG purchased under a Series A Extension Preferred Stock Purchase Agreement (the “Series A Extension Purchase Agreement”) 6,500,000 additional shares of Series A Preferred Stock at $1.00 per share, which consisted of the Series A Milestone Shares and the Additional Series A Preferred Shares discussed above, resulting in proceeds, net of $39 in issuance costs, of $6.5 million. This agreement also provided that the Company could sell up to 2,000,000 additional shares at $1.00 per share to existing stockholders deemed accredited investors within 45 days of the December 26, 2013 closing.

In January 2014, the Company issued 1,680,000 shares of Series A Preferred Stock to eight of the Series A Investors at $1.00 per share, as provided for as Additional Closings under the Series A Extension Purchase Agreement, resulting in proceeds, net of $7 in issuance costs, of $1.7 million. The Company recorded this issuance at its fair value of $1.08 per share, totaling $1.8 million before financing costs, resulting in a discount on this issuance in the amount of $134, which amount was being amortized out of the carrying value of Series A Preferred Stock over the expected redemption period, which was three years from July 14, 2017, the date of the First Tranche Closing of the Series C Preferred Stock Financing (each such term as defined below), or July 14, 2020 (the “Redemption Period”). Such amortization totaled $7 and $1 for the three months ended June 30, 2019 and 2018, respectively, and $7 and $2 for the six months ended June 30, 2019 and 2018, respectively, which, for the three and six months ended June 30, 2019, includes $5 of previously unaccreted discount on issuance at the time of conversion to shares of common stock.

Holders of Series C Preferred Stock had a higher liquidation preference than the holders of Series A Preferred Stock and Series B Preferred Stock. (See Liquidation Preferences note below.)

Issuance of Series B Redeemable Convertible Preferred Stock

On May 23, 2014, the Company entered into the Series B Preferred Stock Purchase Agreement (the “Series B Purchase Agreement”) with TPG. Pursuant to the Series B Purchase Agreement, the Company issued 13,043,478 shares (the “Series B Initial Closing”) of Series B Preferred Stock to TPG at a purchase price of $1.15 per share, resulting in proceeds, net of $56 in issuance costs, of $15.0 million.

The Series B Purchase Agreement also provided for the sale of 4,347,826 additional shares of Series B Preferred Stock (the “Series B Milestone Shares”) to TPG at a purchase price of $1.15 per share upon the Company’s achievement of specified Milestone Events, as defined in the Series B Purchase Agreement, involving the Company’s Phase 2b/3 clinical trial of nalbuphine ER in patients with uremic pruritus; its planned Phase 2 clinical trial of nalbuphine ER in patients with pruritus associated with prurigo nodularis; and a pending patent application. In the event the Milestone Events were not achieved, TPG had the right to purchase the Series B Milestone Shares, in full or in part, under the same terms and conditions as the Series B Initial Closing, at a purchase price of $1.15 per share, on or before November 30, 2015.

In addition, TPG had the right to purchase, on the same terms and conditions as the Series B Initial Closing, including the $1.15 per share purchase price, the lesser of 4,347,826 additional shares of Series B Preferred Stock and the number of shares equal to 25% of the total number of shares it previously purchased for cash under the Series B Purchase Agreement (the “Additional Series B Shares”). This additional right was exercisable until the date six months after the completion date of the Company’s Phase 2b/3 clinical trial of nalbuphine ER in patients with uremic pruritus.

On October 30, 2014, TPG exercised its rights described above and purchased under an Additional Closing Agreement (the “Series B Second Closing”) 8,695,652 additional shares of Series B Preferred Stock at $1.15 per share, which consisted of the Series B Milestone Shares and the Additional Series B Shares. This agreement also provided for the Company to sell 869,565 additional shares of Series B Preferred Stock at $1.15 per share to an existing stockholder. The Series B Second Closing resulted in proceeds, net of $19 in issuance costs, of $11.0 million. The Company recorded this issuance at its fair value of $1.10 per share, totaling $10.5 million, net of financing costs, resulting in a premium on this issuance in the amount of $478, which amount was being accreted into the carrying value of the Series B Preferred Stock over the Redemption Period. Such accretion totaled $26 and $5 for the three months ended June 30, 2019 and 2018, respectively, and $31 and $10 for the six months ended June 30, 2019 and 2018, respectively, which includes $22, for the three and six months ended June 30, 2019 of unaccreted premium on issuance at the time of conversion to shares of common stock.

Holders of Series C Preferred Stock had a higher liquidation preference than the holders of Series A Preferred Stock and Series B Preferred Stock. (See Liquidation Preferences note below)

Issuance of Series C Redeemable Convertible Preferred Stock

On July 14, 2017, the Company entered into the Series C Purchase Agreement with TPG and other institutional investors (the “Series C Initial Purchasers”) for the issuance of $50.5 million of its Series C Preferred Stock. The Series C Purchase Agreement provided for the Company’s Series C Preferred Stock to be issued in two tranches, with the closing of the first tranche on July 14, 2017 (the “First Tranche Closing”) and the closing of the second tranche to occur following a determination by the Company’s board of directors that the Company’s cash and cash equivalents at such time are not sufficient to fund its operations for a period of three months following such determination (the “Second Tranche Closing”). Upon the First Tranche Closing, the Company issued 20,547,946 shares of its Series C Preferred Stock at a purchase price of $1.46 per share, resulting in proceeds of $29.7 million, net of issuance costs of $291.

Also party to the Series C Purchase Agreement were eleven holders of the Company’s Convertible Notes (together with the Initial Purchasers and the Series C Additional Purchasers, as defined below, the “Series C Investors”). Concurrently with the First Tranche Closing and pursuant to the Series C Purchase Agreement, the outstanding principal on the Company’s Convertible Notes, totaling $10.6 million, and all accrued interest thereon, totaling $564, were automatically converted at the Mandatory Conversion Price of $1.095 per share, and the Company issued 10,181,233 shares of its Series C Preferred Stock in full settlement of the Convertible Notes.

The Series C Purchase Agreement provided for a subsequent closing (the “Special Closing”), on the same terms and conditions as the First Tranche Closing, including the $1.46 per share purchase price, and on October 11, 2017, the Special Closing occurred, resulting in the issuance to two additional investors (the “Series C Additional Purchasers”) of 101,707 shares of the Company’s Series C Preferred Stock, at a purchase price of $1.46 per share, resulting in proceeds of $129, net of issuance costs of $19.

On November 12, 2017, one of the Series C Additional Purchasers purchased its second tranche shares pursuant to an election under the Series C Purchase Agreement, resulting in the issuance of 55,621 shares of the Company’s Series C Preferred Stock at a purchase price of $1.46 per share, resulting in proceeds of $81.

On August 28, 2018, the Company amended the Series C Purchase Agreement to provide that a portion of the shares of Series C Preferred Stock that would otherwise be issued and sold at the Second Tranche Closing would instead be issued and sold at a third tranche closing (the “Third Tranche Closing”), with such closing to occur following a determination by the Company’s board of directors that the Company’s cash and cash equivalents at such time are not sufficient to fund its operations for a period of three months following such determination.

On August 30, 2018, the Company completed the Second Tranche Closing, resulting in the issuance of 7,211,165 shares of the Company’s Series C Preferred Stock, at a purchase price of $1.46 per share, resulting in proceeds of $10.5 million, net of issuance costs of $32.

On January 18, 2019, the Company completed the Third Tranche Closing, resulting in the issuance of 6,849,315 shares of the Company’s Series C Preferred Stock, at a purchase price of $1.46 per share, resulting in proceeds of $10.0 million, net of issuance costs of $37. At such time, the Series C redeemable convertible preferred stock liability of $1.1 million was reclassified as Series C Preferred Stock.

Series C Redeemable Convertible Preferred Stock Liability and Changes in Fair Value

As discussed above, the Series C Purchase Agreement provided for the issuance and sale of Series C Preferred Stock in three separate tranches. The tranches represented a freestanding financial instrument under ASC 480 and required fair value accounting until they were settled. The Company recognized a liability on its Consolidated Balance Sheet for the obligations under this financial instrument. The Company adjusted this liability to fair value at each reporting date, as applicable, and recognized any changes in fair value of the Series C Preferred Stock in its Consolidated Statements of Operations as a component of other income (expense). The Company continued to recognize any changes in the fair value of this liability through the closing of the third tranche.

Accordingly, for the year ended December 31, 2018, the Company recorded the Series C redeemable convertible preferred stock liability at its fair value of $2.1 million, with a corresponding charge to other income (expense) in the Company’s Consolidated Statement of Operations. Upon the Second Tranche Closing in August 2018, as described above, $1.0 million was reclassified to Series C Preferred Stock. As a result, at December 31, 2018, the fair value of this liability, relating to the outstanding third tranche, was determined to be $1.1 million and was reclassified to Series C Preferred Stock upon the Third Tranche Closing in January 2019.

The fair value of the Series C redeemable convertible preferred stock liability was estimated as the excess, if any, of the fair value per share of the Company’s Series C Preferred Stock, as described below under Redemption Rights, over the purchase price of any outstanding tranches to be sold pursuant to the Series C Purchase Agreement.

Holders of Series C Preferred Stock had a higher liquidation preference than the holders of Series A Preferred Stock and Series B Preferred Stock. (See Liquidation Preferences note below.)

As of June 30, 2019, there were no redeemable convertible preferred shares outstanding as a result of the conversion into common shares in connection with the IPO. As of December 31, 2018, redeemable convertible preferred stock consisted of the following (in thousands, except share amounts).

	As of December 31, 2018
	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Carrying Value		Liquidation Preference		Common Shares Issuable Upon Conversion
Series A redeemable convertible preferred stock		15,387,923		15,387,923	$	21,033	$	20,469		2,154,572
Series B redeemable convertible preferred stock		22,608,695		22,608,695		33,686		32,900		3,011,392
Series C redeemable convertible preferred stock		48,200,412		38,097,672		61,023		59,798		4,311,279
		86,197,030		76,094,290	$	115,742	$	113,167		9,477,243

Dividends

Dividends on outstanding shares of Series A, Series B and Series C Preferred Stock accrued at a rate of 6% per annum on their original purchase price of $1.00, $1.15 and $1.46 per share, respectively (the “Accruing Dividends”), whether or not declared, and were cumulative. However, Accruing Dividends on the Company’s outstanding redeemable convertible preferred stock were payable only when, as and if declared by the Company’s board of directors, or upon liquidation, redemption or conversion. No dividends were payable to the holders of the Company’s common stock unless equivalent dividends had been declared and paid on the Company’s outstanding Series A, Series B and Series C Preferred Stock. No dividends had been declared or paid by the Company through the date of the IPO. Accruing Dividends totaled $18.4 million through the date of the IPO, at which time they were converted into common shares. Accruing Dividends totaled $16.2 million as of December 31, 2018. Such amounts are included in the carrying values of Series A, Series B and Series C Preferred Stock, and in the accumulated deficit on the Company’s Condensed Consolidated Balance Sheets at December 31, 2018.

Liquidation Preferences

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or deemed liquidation event, the holders of shares of Series C Preferred Stock then outstanding were entitled to be paid out of the assets of the Company that were available for distribution to its stockholders, before any payments were to be made to the holders of Series A Preferred Stock, Series B Preferred Stock or common stock by reason of their ownership thereof, an amount per share equal to the Series C Preferred Stock original issue price of $1.46 per share, plus any Accruing Dividends accrued but unpaid thereon, whether or not declared, together with any other dividends declared but unpaid thereon. If upon any such liquidation, dissolution or winding up of the Company or deemed liquidation event, the assets of the Company available for distribution to its stockholders were insufficient to pay the holders of shares of Series C Preferred Stock the full amount to which they were entitled, the holders of Series C Preferred Stock were entitled to share ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares of Series C Preferred Stock held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or deemed liquidation event, the holders of shares of Series A Preferred Stock and Series B Preferred Stock then outstanding were entitled to be paid out of the assets of the Company available for distribution to its stockholders after the payment of all preferential amounts required to be paid to the holders of shares of Series C Preferred Stock but before any payments were made to the holders of common stock by reason of their ownership thereof, (i) an amount per share equal to the Series A original issue price of $1.00 per share in the case of the Series A Preferred Stock, plus any Accruing Dividends accrued but unpaid thereon, whether or not declared, together with any other dividends declared but unpaid thereon, and (ii) an amount per share equal to the Series B original issue price of $1.15 per share in the case of the Series B Preferred Stock, plus any Accruing Dividends accrued but unpaid thereon, whether or not declared, together with any other dividends declared but unpaid thereon. If upon any such liquidation, dissolution or winding up of the Company or deemed liquidation event, the assets of the Company available for distribution to its stockholders were insufficient to pay the holders of shares of Series A Preferred Stock and Series B Preferred Stock the full amount to which they were entitled (after the payment in full of all preferential amounts required to be paid to the holders of shares of Series C Preferred Stock), the holders of shares of Series A Preferred Stock and Series B Preferred Stock were entitled to share ratably in any distribution of the assets available for distribution in respect of such shares in proportion to the respective amounts which would otherwise be payable in respect of the share of Series A Preferred Stock and Series B Preferred Stock held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or deemed liquidation event, after the payment of all preferential amounts required to be paid to the holders of shares of redeemable convertible preferred stock, the remaining assets of the Company available for distribution to its stockholders were to be distributed among the holders of the shares of redeemable convertible preferred stock and common stock, in proportion to the number of shares held by each such holder, treating for this purpose all such securities as if they had been converted into common stock pursuant to the terms of the Company’s certificate of incorporation immediately prior to such dissolution, liquidation or winding up of the Company.

Redemption Rights

The Company’s certificate of incorporation provided that, unless prohibited by Delaware law governing distributions to stockholders, shares of the redeemable convertible preferred stock were to be redeemed by the Company in three annual installments commencing not more than 60 days after receipt by the Company, at any time on or after July 14, 2020, of written notice from the holders of at least a majority of the outstanding shares of redeemable convertible preferred stock, voting together as a single class on an as-converted basis, requesting redemption of all shares of redeemable convertible preferred stock (a “Redemption Request”).

In that event, unless prohibited by Delaware law governing distributions to stockholders, generally in connection with an insolvent corporation, shares of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock, respectively, were to be redeemed by the Company at a price equal to the greater of (A) the applicable original issue price per share for such series of redeemable convertible preferred stock, plus any Accruing Dividends accrued but unpaid thereon, whether or not declared, together with any other dividends declared but unpaid thereon, and (B) the fair market value per share of Series A Preferred Stock, Series B Preferred Stock or Series C Preferred Stock, as the case may be, as of the date of the Company’s receipt of the Redemption Request. For purposes of these redemption rights, the fair market value per share of the Series A Preferred Stock was defined as the value per share of Series A Preferred Stock as mutually agreed upon by the Company and the holders of 60% of the shares of Series A Preferred Stock then outstanding, and, in the event that they were unable to reach agreement, by a third-party appraiser agreed to by the Company and the holders of a majority of the shares of Series A Preferred Stock then outstanding; the fair market value per share of the Series B Preferred Stock was defined as the value per share of Series B Preferred Stock as mutually agreed upon by the Company and the holders of 60% of the shares of Series B Preferred Stock then outstanding, and, in the event that they were unable to reach agreement, by a third-party appraiser agreed to by the Company and the holders of a majority of the shares of Series B Preferred Stock then outstanding; and the fair market value per share of the Series C Preferred Stock was defined as the value per share of Series C Preferred Stock as mutually agreed upon by the Company and the holders of 66 2/3% of the shares of Series C Preferred Stock then outstanding, and, in the event that they were unable to reach agreement, by a third-party appraiser agreed to by the Company and the holders of a majority of the shares of Series C Preferred Stock then outstanding.

As a result of the redemption rights described above, the carrying values of Series A Preferred Stock of $21.0 million, Series B Preferred Stock of $33.7 million, and Series C Preferred Stock of $61.0 million as of December 31, 2018, have been classified as temporary equity, and are presented between liabilities and stockholders’ equity (deficit) on the Company’s Condensed Consolidated Balance Sheets in accordance with ASC 480. The Company was accreting the carrying value of the redeemable convertible preferred stock up to the expected redemption value over the estimated Redemption Period. The accretion included cumulative unpaid and undeclared Accruing Dividends as well as additional increases, if any, when the fair value of the redeemable convertible preferred stock exceeded the liquidation value at any point during the Redemption Period. Upon the IPO, all redeemable convertible preferred shares and Accruing Dividends thereon converted to common shares and all previously unaccreted amounts were fully accreted to the expected redemption value.

At December 31, 2018, the fair values of the Company’s Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock were determined utilizing a probability-weighted modeling approach that included both IPO and non-IPO based scenarios. The non-IPO based scenarios included the fair value estimates of the Company’s common stock, before marketability discount, of $0.47, and each issue of its redeemable convertible preferred stock of: $0.82 for its Series A Preferred Stock; $0.86 for its Series B Preferred Stock; and $1.44 for its Series C Preferred Stock, each calculated at December 31, 2017, as there were no clinical development milestones either achieved or not achieved during the period, and it was deemed that the Company’s total equity value had not changed to any significant degree through the December 31, 2018 measurement date. Additional significant inputs utilized for the non-IPO based scenario was a probability factor of 60% and a marketability discount of 20% applied in arriving at the fair value of the common stock. The IPO-based scenario utilized an expected pre-money valuation upon IPO; cost of equity estimate of 15%; estimated time to IPO date of 0.38 years; and a probability factor of 40%.

At December 31, 2017, the fair value of the Company’s Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock was determined utilizing the OPM; whereby each class of stock is modeled as a call option with a unique claim on the assets of the Company. Stock characteristics that were incorporated directly into the option valuation model include liquidation preferences, participation features, convertibility features and ratios, and value-sharing between classes of stock. The Company’s equity value was estimated by employing a back-solving approach to determine its implied equity value at December 31, 2017 based on the initial closing of the Series C Preferred Stock financing completed in July 2017. A Black-Scholes options pricing approach was utilized under the OPM to determine the fair value of each security, with significant inputs including a $1.44 fair value of the Series C Preferred Stock, a risk-free rate of 1.95%, volatility of 78.0% and a probability-weighted estimate of time to liquidity event of 2.71 years.

Financing costs of approximately $166 that were netted against the proceeds from the 2013 and 2012 Series A Preferred Stock financings were being accreted to Series A Preferred Stock over the period from their respective issuance dates to the earliest redemption date of July 14, 2020. The Company recorded $6 and $1 in accretion for financing costs for the three months ended June 30, 2019 and 2018, respectively, and $7 and $2 for the six months ended June 30, 2019 and 2018, respectively, which, for the three and six months ended June 30, 2019 includes $5 of previously unaccreted financing costs at the time of the conversion of the Series A Preferred Stock into shares of the Company’s common stock. In addition, the investor rights/obligation that was allocated from proceeds from the Series A Preferred Stock financings of $2.8 million, less $520 representing its fair value on the date of its exercise as noted above, was being accreted over the Redemption Period. The Company recorded $70 and $13 in accretion of investor rights/obligation in the three months ended June 30, 2019 and 2018, respectively, and $84 and $27 for the six months ended June 30, 2019 and 2018, respectively, which, for the three and six months ended June 30, 2019 includes $61 of previously unaccreted investor rights/obligations at the time of the conversion of the Series A Preferred Stock into shares of the Company’s common stock.

Financing costs of approximately $76 that were netted against the proceeds from the 2014 Series B Preferred Stock financings were being accreted to Series B Preferred Stock over the period from their respective issuance dates to the earliest redemption date of July 14, 2020. The Company recorded $3 and $1 in accretion for financing costs in the three months ended June 30, 2019 and 2018, respectively, and $4 and $1 for the six months ended June 30, 2019 and 2018, respectively, which, for the three and six months ended June 30, 2019 includes $3 of previously unaccreted financing costs at the time of conversion of the Series B Preferred Stock into shares of the Company’s common stock. In addition, the investor rights/obligation that was allocated from proceeds from the Series B Preferred Stock financings of $2.0 million was being accreted over the remaining Redemption Period discussed above. The Company recorded $98 and $19 in accretion of Series B Preferred Stock investor rights/obligation in the three months ended June 30, 2019 and 2018, respectively, and $117 and $38 for the six months ended June 30, 2018 and 2019, respectively, which, for the three and six months ended June 30, 2019 includes $85 of previously unaccreted investor rights/obligations at the time of the conversion of the Series B Preferred Stock into shares of the Company’s common stock.

Financing costs of approximately $379 that were netted against the proceeds from the 2017, 2018 and 2019 Series C Preferred Stock financings were being accreted to Series C Preferred Stock over the period from their respective issuance dates to the earliest redemption date of July 14, 2020. The Company recorded $188 and $26 in accretion for financing costs in the three months ended June 30, 2019 and 2018, respectively, and $223 and $52 for the six months ended June 30, 2019 and 2018, respectively, which, for the three and six months ended June 30, 2019 includes $164 of previously unaccreted financing costs at the time of conversion of the Series C Preferred Stock into shares of the Company’s common stock.

Optional Conversion

Each holder of Series A, Series B or Series C Preferred Stock was able to convert any or all of such holder’s redeemable convertible preferred stock into common stock at any time. Each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock was convertible into such number of shares of common stock as determined by dividing the original issue price of such series by the conversion price for such series in effect at the time of conversion. As of December 31, 2018, each share of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock was convertible into common stock at a one-to-one conversion ratio. As of June 30, 2019, there were no redeemable convertible preferred shares outstanding as a result of the conversion into common shares in connection with the IPO.

In addition, upon conversion of shares of Series A, Series B or Series C Preferred Stock, a holder was entitled to receive, at the election of the holder, either (i) payment in cash of any Accruing Dividends declared but unpaid thereon, or (ii) such number of shares of common stock as determined by dividing the Accruing Dividends for such share of Series A, Series B or Series C Preferred Stock, by the applicable conversion price for such series of redeemable preferred stock in effect at the time of conversion. The conversion prices for Series A, Series B or Series C Preferred Stock were subject to adjustment based on certain events specified in the Company’s certificate of incorporation, including anti-dilution adjustments.

Mandatory Conversion

Upon the closing of a qualified public offering of common stock, as defined in the Company’s certificate of incorporation, or approval of (i) the holders of at least 60% of the Series A Preferred Stock then outstanding, voting separately as a class, (ii) the holders of at least 60% of the Series B Preferred Stock then outstanding, voting separately as a class and (iii) the holders of at least 66 2/3% of the Series C Preferred Stock then outstanding, voting separately as a class, all outstanding shares of redeemable convertible preferred stock would have automatically converted into common stock at the then-applicable conversion rate for such shares. At June 30, 2019, there were no redeemable convertible preferred shares outstanding as a result of the conversion into common shares at a one-for-9.5 conversion ratio, in connection with the IPO.

Voting Rights

Prior to the IPO, and except as otherwise provided by law or by the other provisions of the Company’s certificate of incorporation, the holders of redeemable convertible preferred stock were entitled to vote as one class with the holders of common stock on any matter presented to the stockholders of the Company for their action or consideration at any meeting of stockholders of the Company (or by written consent of stockholders in lieu of a meeting), and each holder of outstanding shares of redeemable convertible preferred stock was entitled to cast the number of votes equal to the number of whole shares of common stock into which the shares of redeemable convertible preferred stock held by such holder were convertible as of the record date for determining stockholders entitled to vote on the matter. The holders of record of the shares of the Company’s Series B Preferred Stock, exclusively and as a separate class, were entitled to elect two directors of the Company, the holders of record of the shares of Series C Preferred Stock, exclusively, and as a separate class, were entitled to elect three directors of the Company, and the holders of record of the shares of common stock of the Company, exclusively and as a separate class, were entitled to elect two directors of the Company.

Registration Rights

The holders of shares of the Company’s common stock issued upon conversion of shares of Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock have certain registration rights as set forth in an investors’ rights agreement between the Company and certain of its stockholders.

Stock-Based Awards

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Awards

9.	Stock-Based Awards

In April 2019, the Company’s board of directors adopted the 2019 Stock Incentive Plan (the “2019 Plan”), which became effective on May 7, 2019. The 2019 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors are eligible to receive awards under the 2019 Plan. The 2019 Plan is administered by the Company’s board of directors.

Awards may be made under the 2019 Plan for up to such number of shares of the Company’s common stock as is equal to the sum of: i) 1,578,947 shares; plus ii) the number of shares (up to 1,157,894 shares) equal to the number of shares of the Company’s common stock subject to outstanding awards under the 2012 Plan that expire, terminate or are otherwise cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right; plus iii) an annual increase to be added on the first day of each fiscal year, beginning with 2020 and continuing through 2029, equal to the least of (a) 2,105,623 shares of common stock, (b) 4% of the number of outstanding shares of the Company’s common stock on such date, and (c) an amount determined by the Company’s board of directors.

The Company’s 2012 Stock Incentive Plan (the “2012 Plan”), as amended, was adopted by the Company’s board of directors and stockholders. The Company’s board of directors administers the 2012 Plan. The 2012 Plan provides for the issuance of stock-based awards to the Company’s employees, officers and directors, as well as non-employee/consultants and advisors to the Company.

Options granted under the Plan have a maximum term of ten years. Options vest over four years based on varying vesting schedules including: 25% vesting on the first anniversary date of grant and the balance ratably over the next 36 months or vesting in equal monthly or quarterly installments over four years. As of June 30, 2019 and December 31, 2018, respectively, options to purchase 1,044,759 and 1,077,148 shares of common stock were granted and outstanding, net of cancelations.

In April 2019, the Company’s board of directors adopted a resolution effective on May 7, 2019 that no further stock options or other equity-based awards may be granted under the 2012 Plan.

During the six months ended June 30, 2018, options to purchase 146,103 shares of the Company’s common stock were granted under the 2012 Plan.

During the six months ended June 30, 2018, options were exercised for 5,679 shares of common stock.

No options were forfeited during the six months ended June 30, 2018.

No options expired during the six months ended June 30, 2018.

A summary of the Company’s option activity for the six months ended June 30, 2019 for the 2012 Plan and the 2019 Plan is as follows:

	Number of Option Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2018		1,077,148		$	3.90		7.8	$	5,857
Granted		667,102		$	10.09
Forfeited		(35,745	)	$	7.67
Expired		(5,592	)	$	3.04
Exercised		(14,736	)	$	2.60
Outstanding as of June 30, 2019		1,688,177		$	6.26		8.3	$	3,946
Options exercisable as of June 30, 2019		592,456		$	2.69		5.6	$	2,853
Options unvested as of June 30, 2019		1,095,721		$	8.19		9.4	$	1,093

The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan and the 2019 Plan recognized in the Condensed Consolidated Statements of Operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development expense	$	30	$	39	$	52	$	75
General and administrative expense		207		63		331		115
	$	237	$	102	$	383	$	190

In April 2019, the Company’s board of directors adopted the 2019 Employee Stock Purchase Plan (the “2019 ESPP”), which became effective on May 7, 2019. The 2019 ESPP is administered by the Company’s board of directors.

The number of shares of the Company’s common stock that have been approved to be issued under the 2019 ESPP is equal to the sum of: i) 155,106 shares; plus ii) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2020 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2029, equal to the least of (a) 526,315 shares of common stock, (b) 1% of the number of outstanding shares of the Company’s common stock on such date, and (c) an amount determined by the Company’s board of directors.

All of the Company’s employees are eligible to participate in the 2019 ESPP, provided that:

•

such person is customarily employed by the Company for more than 20 hours a week and for more than five months in a calendar year;

•

such person has been employed by the Company for at least three months prior to enrolling in the 2019 ESPP; and

•

such person was an employee of the Company on the first day of the applicable offering period under the 2019 ESPP.

Income Taxes

6 Months Ended

Jun. 30, 2019

Income Tax Disclosure [Abstract]

Income Taxes

10.	Income Taxes

During the three and six months ended June 30, 2019 and 2018, the Company maintained a full valuation allowance on deferred tax assets. Therefore, the Company has not recorded a provision for income taxes.

Net Loss per Share

6 Months Ended

Jun. 30, 2019

Earnings Per Share [Abstract]

Earnings Per Share

11.	Net Loss per Share

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company:

	Three Months Ended June 30,						Six Months Ended June 30,
	2019			2018			2019			2018
Net loss	$	(7,346	)	$	(4,858	)	$	(12,148	)	$	(8,909	)
Plus: Dividends accrued on redeemable convertible preferred stock		1,332			175			1,535			370
Plus: Accretion of redeemable convertible preferred stock		(686	)		(1,293	)		(2,239	)		(2,573	)
Adjusted net loss attributable to common stockholders	$	(6,700	)	$	(5,976	)	$	(12,852	)	$	(11,112	)
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted		10,571,736			438,606			5,535,907			436,598
Basic and diluted net loss per common share outstanding	$	(0.63	)	$	(13.62	)	$	(2.32	)	$	(25.45	)

Accretion and dividends included in the table above were calculated through the IPO date.

The Company’s potential dilutive securities, which include stock options and redeemable convertible preferred stock, have been excluded from the computation of diluted net loss per share attributable to common stockholders whenever the effect of including them would be to reduce the net loss per share. In periods where there is a net loss, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The following potential common shares, presented based on shares outstanding as of June 30, 2019 and 2018, were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:

	Shares as of June 30,
	2019		2018
Series A redeemable convertible preferred stock		—		15,387,923
Series B redeemable convertible preferred stock		—		22,608,695
Series C redeemable convertible preferred stock		—		30,886,507
Outstanding stock options		1,688,177		983,849
		1,688,177		69,866,974

Collaborative and Licensing Agreements

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaborative and Licensing Agreements

12.	Collaborative and Licensing Agreements

The Company enters into collaborative and licensing agreements with pharmaceutical companies to in-license, develop, manufacture and/or market products that fit within its business strategy.

Endo Pharmaceuticals Inc.

In May 2011, the Company entered into an agreement with Penwest Pharmaceuticals Co. (“Penwest”) (subsequently merged into its parent, Endo Pharmaceuticals Inc. (“Endo”) for an exclusive worldwide sublicensable license under certain patent rights and know-how controlled by Penwest to develop and commercialize products incorporating nalbuphine hydrochloride in any formulation, including an extended release formulation such as nalbuphine ER, in all fields and for any use.

Under the license agreement, the Company paid Penwest a non-creditable, non-refundable upfront license fee of $25. The Company may also become obligated to make milestone payments to Endo of $250, which would become due upon the successful completion of the first Phase 3 clinical trial of a licensed product candidate, such as the PRISM trial, and $750, which would become due upon the marketing approval of a licensed product in the United States, and to pay mid-single-digit royalties based on net sales of the licensed products by the Company, its affiliates and sublicensees. In addition, the Company is obligated to pay Endo a low-to-mid double-digit percentage of certain income it receives from sublicensees, based on the date of the definitive agreement under which the sublicense was granted.

The Company’s royalty obligation with respect to each licensed product in each country commences upon the first commercial sale of the product in that country and extends until the later of the expiration, unenforceability or invalidation of the last valid claim of any licensed patent or application covering the licensed product in the country or the expiration of 10 years after the first commercial sale of the licensed product in the country, which period is referred to as the royalty term. Upon the expiration of the royalty term for a product in a country, the Company is thereafter obligated to pay a low single-digit know-how and trademark royalty.

Under the agreement, the Company has granted Endo a non-exclusive, royalty-free (except for pass-through payments to third parties), sublicensable license under its relevant patent rights, to use any improvement the Company makes to Endo’s controlled release technology, for any product other than the products under which it is licensed by Endo.

Both the Company and Endo have the right to terminate the agreement if the other party materially breaches the agreement and fails to cure the breach within specified cure periods. Endo also has the right to terminate in the event the Company undergoes specified bankruptcy, insolvency or liquidation events, and the Company has the right to terminate the agreement at its convenience at any time on 180 days’ notice to Endo. Additionally, if the Company or any of the Company’s sublicensees challenge the validity or enforceability of any licensed patent rights covering a licensed product, and that challenge is not terminated within a specified period, the agreement will immediately terminate and all licenses granted under the agreement shall be revoked.

Upon termination of the agreement, the Company must transfer to Endo all regulatory filings and approvals relating to the development, manufacture or commercialization of the licensed products and all trademarks, other than the Company’s corporate trademarks, then being used in connection with the licensed products. If the agreement is terminated under certain specified circumstances, the Company will be deemed to have granted Endo a perpetual, royalty-free (except for pass-through payments to third parties), worldwide, exclusive, sublicensable license, under any improvements the Company made to the licensed know-how, and any related patent rights the Company has, to manufacture and commercialize the licensed products.

Exclusive License Agreement with Rutgers

On November 6, 2018, the Company entered into an agreement with Rutgers, The State University of New Jersey (“Rutgers”) for an exclusive, worldwide, sublicensable license under certain patent rights controlled by Rutgers and for a non-exclusive, worldwide, sublicensable license under certain know-how controlled by Rutgers, in each case to develop and commercialize products incorporating nalbuphine for any human or animal use.

Upon entering into the license agreement, the Company paid Rutgers a minimal upfront license issue fee, which was recorded as R&D expense in 2018 and agreed to pay Rutgers a minimal annual license fee. The Company may become obligated to make milestone payments to Rutgers in the aggregate of up to $331 based on the achievement of certain clinical, regulatory and sales milestones. The Company has also agreed to pay Rutgers a low single-digit percentage of certain income it receives from sublicensees and to pay tiered low single-digit royalties based on net sales of licensed products by the Company and its affiliates and sublicensees.

The Company’s royalty obligation with respect to each licensed product in each country commences on the date of the first commercial sale of the licensed product in that country following receipt of marketing approval and extends until the later of the date of expiration, unenforceability or invalidation of the last valid claim of any licensed patent or patent application covering the licensed product in the country and 10 years after the first commercial sale of the first licensed product sold anywhere in the world, which period is referred to as the royalty term. Upon the expiration of the royalty term for a licensed product in a country, the license granted to the Company under the agreement shall become perpetual, fully paid-up, irrevocable and royalty-free in such country. The royalty is subject to reduction in certain circumstances.

Restructuring Agreement with MentiNova, Inc.

On November 6, 2018, concurrent with the signing of the agreement with Rutgers described above, the Company entered into a restructuring agreement with MentiNova, Inc. (“MentiNova”) for the purchase of specified information and know-how, specified contractual rights and benefits, and all books and records of MentiNova related thereto (collectively, the “Acquired Assets”).

Upon entering into the license agreement, the Company paid MentiNova an aggregate upfront payment of $119, which was recorded as R&D expense in 2018, subject to specified closing adjustments. The Company may become obligated to make milestone payments to MentiNova in the aggregate of up to $1,188 based on the achievement of certain clinical and regulatory milestones as well as tiered low single-digit royalties based on net sales of products containing nalbuphine as the sole active pharmaceutical ingredient that are developed by the Company using the Acquired Assets or the intellectual property licensed to the Company under the Rutgers agreement described above (the “Rutgers IP”) for indications that are within the scope of the Rutgers IP. The royalty is subject to reduction in certain circumstances.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

13.	Commitments and Contingencies

A significant portion of the Company’s development activities are outsourced to third parties under agreements, including with clinical research organizations, and contract manufacturers in connection with the production of clinical trial materials. These arrangements may require the Company to pay termination costs to the third parties for reimbursement of costs and expenses incurred in the event of the orderly termination of contractual services.

The Company also has commitments under lease and licensing agreements (Note 4 and Note 12).

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Unaudited Interim Financial Information

Fair Value Measurements

Level 1—Observable inputs—quoted prices in active markets for identical assets and liabilities.

Level 3—Unobservable inputs—includes amounts derived from valuation models where one or more significant inputs are unobservable and require the company to develop relevant assumptions.

	Balance December 31, 2018		Level 1		Level 2		Level 3
Financial liabilities
Series C redeemable convertible preferred stock liability	$	1,096	$	—	$	—	$	1,096
Obligation for loan success fee		460		—		—		460
	$	1,556	$	—	$	—	$	1,556

The following table represents a roll-forward of the fair value of Level 3 instruments (significant unobservable inputs):

	June 30,			December 31,
	2019			2018
Financial liabilities
Balance at beginning of year⁽¹⁾	$	1,556		$	322
Unrealized loss on Series C redeemable convertible preferred stock liability		—			2,105
Unrealized loss on obligation for loan success fee		215			138
Net settlements⁽²⁾		(1,771	)		(1,009	)
Ending balance	$	—		$	1,556

(1)	The balance at January 1, 2018 relates to the obligation for the loan success fee.

(2)

Deferred Offering Costs

Basic and Diluted Net Income (Loss) per Common Share

Recently Adopted Accounting Pronouncements

Recently Issued Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis

	Balance December 31, 2018		Level 1		Level 2		Level 3
Financial liabilities
Series C redeemable convertible preferred stock liability	$	1,096	$	—	$	—	$	1,096
Obligation for loan success fee		460		—		—		460
	$	1,556	$	—	$	—	$	1,556

Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation

The following table represents a roll-forward of the fair value of Level 3 instruments (significant unobservable inputs):

	June 30,			December 31,
	2019			2018
Financial liabilities
Balance at beginning of year⁽¹⁾	$	1,556		$	322
Unrealized loss on Series C redeemable convertible preferred stock liability		—			2,105
Unrealized loss on obligation for loan success fee		215			138
Net settlements⁽²⁾		(1,771	)		(1,009	)
Ending balance	$	—		$	1,556

(1)	The balance at January 1, 2018 relates to the obligation for the loan success fee.

(2)

Prepaid Expenses (Tables)

6 Months Ended

Jun. 30, 2019

Prepaid Expense Current [Abstract]

Schedule Of Prepaid Expenses

Prepaid expenses consist of the following:

	As of June 30, 2019		As of December 31, 2018
Prepaid R&D payments	$	1,765	$	1,337
Prepaid corporate insurance		1,178		59
Other		27		42
	$	2,970	$	1,438

Leases (Tables)

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Schedule Of Balance Sheet Information Related To Operating Leases

The following table summarizes the Company’s operating leases as presented on its Condensed Consolidated Balance Sheet as of June 30, 2019:

Assets:
Operating lease right-of-use asset	$	350
Liabilities:
Operating lease liabilities, current portion		91
Operating lease liabilities, long term portion		308
Total operating lease liabilities	$	399

Future Minimum Lease Payments for Non-cancellable Operating Leases

Future minimum lease payments under the operating leases are as follows as of June 30, 2019:

2019	$	68
2020		138
2021		138
2022		131
2023		24
Total lease payments		499
Less: imputed discount rate		(100	)
Carrying value of operating lease liabilities	$	399

Accrued Expenses (Tables)

6 Months Ended

Jun. 30, 2019

Payables And Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of the following:

	As of June 30, 2019		As of December 31, 2018
Accrued research projects	$	3,044	$	942
Accrued professional fees		561		477
Accrued compensation and benefits		602		584
Other		144		70
	$	4,351	$	2,073

Term Loan Payable (Tables)

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Schedule of Components of Interest Expense of Term Loan

	Three Months Ended June 30,		Six Months Ended June 30,
	2018		2018
Interest payments	$	34	$	114
Amortization of financing costs		5		19
Accrual of final and amendment fees		7		24
Accretion of the Success Fee		5		17
	$	51	$	174

Common Stock (Tables)

6 Months Ended

Jun. 30, 2019

Common Stock Number Of Shares Par Value And Other Disclosures [Abstract]

Schedule of Common Stock Reserved for Future Issuance

	June 30, 2019		December 31, 2018
Shares of common stock reserved for conversion of Series A preferred stock outstanding		—		2,154,572
Shares of common stock reserved for conversion of Series B preferred stock outstanding		—		3,011,392
Shares of common stock reserved for conversion of Series C preferred stock outstanding		—		4,311,279
Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan		1,044,759		1,213,018
Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan		1,578,947		—
Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan		155,106		—
		2,778,812		10,690,261

Redeemable Convertible Preferred Stock (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure Of Redeemable Convertible Preferred Stock [Abstract]

Schedule of Redeemable Convertible Preferred Stock

	As of December 31, 2018
	Preferred Shares Authorized		Preferred Shares Issued and Outstanding		Carrying Value		Liquidation Preference		Common Shares Issuable Upon Conversion
Series A redeemable convertible preferred stock		15,387,923		15,387,923	$	21,033	$	20,469		2,154,572
Series B redeemable convertible preferred stock		22,608,695		22,608,695		33,686		32,900		3,011,392
Series C redeemable convertible preferred stock		48,200,412		38,097,672		61,023		59,798		4,311,279
		86,197,030		76,094,290	$	115,742	$	113,167		9,477,243

Stock-Based Awards (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity

A summary of the Company’s option activity for the six months ended June 30, 2019 for the 2012 Plan and the 2019 Plan is as follows:

	Number of Option Shares			Weighted Average Exercise Price		Weighted Average Contractual Term		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding as of December 31, 2018		1,077,148		$	3.90		7.8	$	5,857
Granted		667,102		$	10.09
Forfeited		(35,745	)	$	7.67
Expired		(5,592	)	$	3.04
Exercised		(14,736	)	$	2.60
Outstanding as of June 30, 2019		1,688,177		$	6.26		8.3	$	3,946
Options exercisable as of June 30, 2019		592,456		$	2.69		5.6	$	2,853
Options unvested as of June 30, 2019		1,095,721		$	8.19		9.4	$	1,093

Schedule of Stock-based Compensation Expenses Recognized

The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan and the 2019 Plan recognized in the Condensed Consolidated Statements of Operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development expense	$	30	$	39	$	52	$	75
General and administrative expense		207		63		331		115
	$	237	$	102	$	383	$	190

Net Loss per Share (Tables)

6 Months Ended

Jun. 30, 2019

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company:

	Three Months Ended June 30,						Six Months Ended June 30,
	2019			2018			2019			2018
Net loss	$	(7,346	)	$	(4,858	)	$	(12,148	)	$	(8,909	)
Plus: Dividends accrued on redeemable convertible preferred stock		1,332			175			1,535			370
Plus: Accretion of redeemable convertible preferred stock		(686	)		(1,293	)		(2,239	)		(2,573	)
Adjusted net loss attributable to common stockholders	$	(6,700	)	$	(5,976	)	$	(12,852	)	$	(11,112	)
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted		10,571,736			438,606			5,535,907			436,598
Basic and diluted net loss per common share outstanding	$	(0.63	)	$	(13.62	)	$	(2.32	)	$	(25.45	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following potential common shares, presented based on shares outstanding as of June 30, 2019 and 2018, were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:

	Shares as of June 30,
	2019		2018
Series A redeemable convertible preferred stock		—		15,387,923
Series B redeemable convertible preferred stock		—		22,608,695
Series C redeemable convertible preferred stock		—		30,886,507
Outstanding stock options		1,688,177		983,849
		1,688,177		69,866,974

Nature of the Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended		12 Months Ended
	May 09, 2019	Apr. 22, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 26, 2013
Stockholders equity reverse stock split		one-for 9.5
Share price									$ 1.00
Proceeds from public offering					$ 51,150
Net income loss			$ (7,346)	$ (4,858)	(12,148)	$ (8,909)	$ (20,500)
Retained earnings accumulated deficit			(100,317)		(100,317)		(109,498)
Cash and cash equivalents, at carrying value			$ 71,387	$ 7,058	$ 71,387	$ 7,058	$ 7,202	$ 22,020
IPO [Member]
Sale of stock during the period	7,000,000
Share price	$ 10.00
Proceeds from public offering	$ 62,100
Underwriting discounts and commissions	4,900
Other offering expenses	$ 3,000

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)

1 Months Ended

6 Months Ended

12 Months Ended

May 31, 2019

Jun. 30, 2019

Dec. 31, 2018

Jan. 01, 2019

Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]

Loan success fee payable

$ 675,000

Deferred offering costs capitalized

$ 1,534,000

Operating lease right-of-use asset

$ 350,000

$ 379,000

Operating lease, liability

399,000

$ 424,000

Series C Convertible Preferred Stock [Member]

Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]

Settlements of fair value liability

1,096,000

1,009,000

Fair Value, Measurements, Recurring [Member]

Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]

Financial liabilities

1,556,000

Settlements of fair value liability

^[1]

$ (1,771,000)

$ (1,009,000)

[1]

Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Financial liabilities
Obligation for loan success fee		$ 460,000
Financial liabilities	$ 0	1,556,000
Series C Preferred Stock [Member]
Financial liabilities
Series C redeemable convertible preferred stock liability		1,096,000
Fair Value, Inputs, Level 1
Financial liabilities
Obligation for loan success fee
Financial liabilities
Fair Value, Inputs, Level 1 \| Series C Preferred Stock [Member]
Financial liabilities
Series C redeemable convertible preferred stock liability
Fair Value, Inputs, Level 2
Financial liabilities
Obligation for loan success fee
Financial liabilities
Fair Value, Inputs, Level 2 \| Series C Preferred Stock [Member]
Financial liabilities
Series C redeemable convertible preferred stock liability
Fair Value, Inputs, Level 3
Financial liabilities
Obligation for loan success fee		460,000
Financial liabilities		1,556,000
Fair Value, Inputs, Level 3 \| Series C Preferred Stock [Member]
Financial liabilities
Series C redeemable convertible preferred stock liability		$ 1,096,000

Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($)
$ in Thousands

6 Months Ended

12 Months Ended

Jun. 30, 2019

Dec. 31, 2018

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Balance at beginning of year

^[1]

$ 1,556

$ 322

Net settlements

^[2]

(1,771)

(1,009)

Ending balance

^[1]

1,556

Series C Redeemable convertible Preferred Stock [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Unrealized loss on Series C redeemable convertible preferred stock liability

2,105

Obligations

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Unrealized loss on Series C redeemable convertible preferred stock liability

$ 215

$ 138

[1]

The balance at January 1, 2018 relates to the obligation for the loan success fee.

[2]

Schedule of Prepaid Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Prepaid Expense Current [Abstract]
Prepaid R&D payments	$ 1,765	$ 1,337
Prepaid corporate insurance	1,178	59
Other	27	42
Prepaid expense	$ 2,970	$ 1,438

Leases - Additional Information (Detail) $ in Thousands		3 Months Ended		6 Months Ended
Leases - Additional Information (Detail) $ in Thousands	Mar. 01, 2013 USD ($) ft²	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Lease	Jun. 30, 2018 USD ($)
Operating lease, weighted average discount rate, percent		13.00%		13.00%
Number of new leases \| Lease				0
Operating Lease, Payments		$ 23	$ 30	$ 57	$ 56
Minimum [Member]
Remaining terms ranging		1 year		1 year
Maximum [Member]
Remaining terms ranging		4 years		4 years
Building [Member]
Leased spaced area \| ft²	5,600
Operating lease term	60 months
Lessee, operating lease, existence of option to terminate				true
Operating lease option to terminate				The Company has the option to terminate the lease after 36 months by providing six months notice along with a payment to the landlord in an amount representing the unamortized cost of tenant improvements plus the unamortized broker’s commission, both of which had been paid by the landlord, and as defined in the agreement.
Building [Member] \| Minimum [Member]
Operating lease rent expense	$ 10
Building [Member] \| Maximum [Member]
Operating lease rent expense	$ 11
Office Equipment [Member]
Operating lease rent expense		$ 31	$ 34	$ 62	$ 54

Schedule of Balance Sheet Operating Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets:
Operating lease right-of-use asset	$ 350	$ 379
Liabilities:
Operating lease liabilities, current portion	91
Operating lease liabilities, long term portion	308		$ 46
Total operating lease liabilities	$ 399	$ 424

Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
Leases [Abstract]
2019	$ 68
2020	138
2021	138
2022	131
2023	24
Total lease payments	499
Less: imputed discount rate	(100)
Carrying value of operating lease liabilities	$ 399	$ 424

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued research projects	$ 3,044	$ 942
Accrued professional fees	561	477
Accrued compensation and benefits	602	584
Other	144	70
Total Accrued expenses	$ 4,351	$ 2,073

Term Loan Payable - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 29, 2018	May 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 29, 2014
Loan success fee payable		$ 675,000
Fair value of success fee liabilities					$ 0		$ 460,000
Non cash charges			$ 163,000	$ 68,000	215,000	$ 80,000
Interest expense				51,000		174,000
Minimum [Member]
Weighted estimated time of exit event							4 months 24 days
Percentage of several potential exit events							5.00%
Maximum [Member]
Weighted estimated time of exit event							3 years 1 month 6 days
Percentage of several potential exit events							40.00%
Term Loan [Member]
Line of credit facility, maximum borrowing capacity								$ 15,000,000
Payment of final fee	$ 450,000
Payment of amendment fee	$ 82,000
Line of credit facility, outstanding borrowings			0		$ 0		$ 0
Loan success fee percentage					4.50%		4.50%
Discount on term loan					$ 15,000,000
Loan discount percentage							13.00%
Interest expense			$ 0	$ 51,000	$ 0	$ 174,000
Term loan A [Member]
Loan success fee payable		$ 675,000

Term Loan Payable - Interest Expense Of Term Loan (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total interest expense		$ 51		$ 174
Term Loan [Member]
Interest payments		34		114
Amortization of financing costs		5		19
Accrual of final and amendment fees		7		24
Accretion of the Success Fee		5		17
Total interest expense	$ 0	$ 51	$ 0	$ 174

Common Stock - Additional Information (Detail) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Common Stock Number Of Shares Par Value And Other Disclosures [Abstract]
Common stock, shares authorized	200,000,000	101,929,904
Common stock, par or stated value per share	$ 0.001	$ 0.001
Common stock, capital shares reserved for future issuance	2,778,812	10,690,261

Common Stock - Shares Reserved For Future Issuances (Detail) - shares	Jun. 30, 2019	Dec. 31, 2018
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	2,778,812	10,690,261
Series A Redeemable convertible Preferred Stock [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		2,154,572
Series B Redeemable convertible Preferred Stock [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		3,011,392
Series C Redeemable convertible Preferred Stock [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		4,311,279
2012 Stock Option And Grant Plan [Member] \| 2012 Stock Incentive Plan [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	1,044,759	1,213,018
2019 Stock Option And Grant Plan [Member] \| 2019 Stock Incentive Plan [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	1,578,947
2019 Stock Option And Grant Plan [Member] \| 2019 Employee Stock Purchase Plan [Member]
Common Stock Reserved For Issuances In The Future Upon Conversion Of Preferred Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	155,106

Redeemable Convertible Preferred Stock - Additional Information (Detail)									1 Months Ended			3 Months Ended			6 Months Ended		12 Months Ended
	May 09, 2019 $ / shares shares	Nov. 12, 2017 USD ($) $ / shares shares	Oct. 11, 2017 USD ($) Investor $ / shares shares	Jul. 14, 2017 USD ($) shares $ / shares	Oct. 30, 2014 USD ($) $ / shares shares	May 23, 2014 USD ($) $ / shares shares	Dec. 26, 2013 USD ($) $ / shares shares	Dec. 04, 2012 USD ($) $ / shares shares	Jan. 18, 2019 USD ($) $ / shares shares	Aug. 30, 2018 USD ($) $ / shares shares	Jan. 31, 2014 USD ($) Number $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 $ / shares	Dec. 31, 2014 USD ($)
Temporary Equity [Line Items]
Preferred Stock, Shares Authorized \| shares												5,000,000			5,000,000		0
Effective Date of restated certificate of incorporation															May 09, 2019
Dividend rate, percentage															6.00%
Share price \| $ / shares							$ 1.00
Convertible preferred stock, settlement terms															In addition, TPG had the right to purchase, on the same terms and conditions as the Series B Initial Closing, including the $1.15 per share purchase price, the lesser of 4,347,826 additional shares of Series B Preferred Stock and the number of shares equal to 25% of the total number of shares it previously purchased for cash under the Series B Purchase Agreement (the “Additional Series B Shares”). This additional right was exercisable until the date six months after the completion date of the Company’s Phase 2b/3 clinical trial of nalbuphine ER in patients with uremic pruritus.
Convertible preferred stock additional shares authorized for issuance \| shares							2,000,000
Preferred stock, share, outstanding \| shares												0			0		0
Dividends payable																	$ 16,200,000
Risk free rate of preferred stock																		1.95%
Volatility rate of preferred stock																		78.00%
Weighted estimate of time to liquidity event of preferred stock																		2 years 8 months 15 days
Conversion ratio of preferred stock to common stock													1				1
Common stock, voting rights															holders of redeemable convertible preferred stock were entitled to vote as one class with the holders of common stock on any matter presented to the stockholders of the Company for their action or consideration at any meeting of stockholders of the Company (or by written consent of stockholders in lieu of a meeting), and each holder of outstanding shares of redeemable convertible preferred stock was entitled to cast the number of votes equal to the number of whole shares of common stock into which the shares of redeemable convertible preferred stock held by such holder were convertible as of the record date for determining stockholders entitled to vote on the matter.
Measeurement Input, Discount for Lack of Marketability [Member]
Temporary Equity [Line Items]
Fair value estimates of common stock discount rate																	0.47
Measurement Input, Probability Factor [Member] \| Non-IPO Based Scenario [Member]
Temporary Equity [Line Items]
Probability factor																	60.00%
Measurement Input, Probability Factor [Member] \| IPO Based Scenario [Member]
Temporary Equity [Line Items]
Probability factor																	40.00%
Measurement Input, Marketability Discount [Member] \| Non-IPO Based Scenario [Member]
Temporary Equity [Line Items]
Fair value marketability discount rate																	20.00%
Measurement Input, Cost of Equity Estimate [Member] \| IPO Based Scenario [Member]
Temporary Equity [Line Items]
Expected pre-money valuation																	15.00%
Measurement Input, Expected Term [Member] \| IPO Based Scenario [Member]
Temporary Equity [Line Items]
Estimated time to IPO date																	4 months 17 days
IPO [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares	7,000,000
Share price \| $ / shares	$ 10.00
Stock issued during period, value, new issues												$ 48,174,000			$ 48,174,000
Accrued dividends converted into common share															$ 18,400
Common Stock [Member] \| IPO [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares												5,500,000			5,500,000
Stock issued during period, value, new issues												$ 5,000			$ 5,000
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock \| shares												0			0		86,197,030
Preferred Stock, Shares Authorized \| shares																	86,197,030
Dividend rate, percentage															6.00%
Preferred stock, value, outstanding																	$ 115,742,000
Preferred stock, share, outstanding \| shares																	76,094,290
Redeemable Convertible Preferred Stock [Member] \| IPO [Member]
Temporary Equity [Line Items]
Preferred stock, share, outstanding \| shares												0			0
Conversion ratio of preferred stock to common stock															0.105
Redeemable Convertible Preferred Stock [Member] \| Series B Purchase Agreement [Member]
Temporary Equity [Line Items]
Stock issued during period shares additional issues \| shares						4,347,826
Number of shares equal to number of shares previously purchased for cash percentage						25.00%
Shares issued, price per share \| $ / shares						$ 1.15
Series A Redeemable convertible Preferred Stock Member [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares							6,500,000	6,000,000
Share price \| $ / shares							$ 1.00	$ 1.00				$ 1.00			$ 1.00
Adjustments to additional paid in capital, stock issued, issuance costs							$ 39,000	$ 128,000
Proceeds from issuance of redeemable convertible preferred stock							$ 6,500,000	5,900,000
Convertible notes payable								$ 564,000
Debt instrument, convertible, conversion price \| $ / shares								$ 0.467
Convertible preferred stock, shares issued upon conversion \| shares								1,207,923
Stock issued during period shares additional issues \| shares								4,000,000							2,500,000
Number of shares equal to number of shares previously purchased for cash percentage															25.00%
Convertible preferred stock, settlement terms															In addition, TPG had the right to purchase, under the same terms and conditions as the Series A Initial Closing, including the $1.00 per share purchase price, the lesser of 2,500,000 additional shares of Series A Preferred Stock (the “Additional Series A Preferred Shares”) and the number of shares of Series A Preferred Stock equal to 25% of the total number of shares of Series A Preferred Stock it previously purchased for cash under the Series A Purchase Agreement.
Shares issued, price per share \| $ / shares											$ 1.08
Preferred stock redemption period											3 years
Preferred stock, value, outstanding																	$ 21,000,000
Series A Redeemable convertible Preferred Stock Member [Member] \| Series A Extension Purchase Agreement [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares											1,680,000
Share price \| $ / shares											$ 1.00
Adjustments to additional paid in capital, stock issued, issuance costs											$ 7,000
Proceeds from issuance of redeemable convertible preferred stock											$ 1,700,000
Number of preferred stock shareholders \| Number											8
Proceeds from issuance of redeemable convertible preferred stock before issuance cost											$ 1,800,000
Preferred stock, discount on shares											$ 134,000
Amortization of stock issuance costs												$ 7,000		$ 1,000	$ 7,000	$ 2,000
Series A Redeemable convertible Preferred Stock Member [Member] \| Series A Extension Purchase Agreement [Member] \| Common Stock [Member]
Temporary Equity [Line Items]
Unaccreted discount												$ 5,000			$ 5,000
Series B Redeemable convertible Preferred Stock Member [Member]
Temporary Equity [Line Items]
Preferred Stock, Shares Authorized \| shares																	22,608,695
Stock issued during period, shares, new issues \| shares					869,565
Share price \| $ / shares					$ 1.15							$ 1.15			$ 1.15
Adjustments to additional paid in capital, stock issued, issuance costs					$ 19,000
Proceeds from issuance of redeemable convertible preferred stock					$ 10,500,000
Shares issued, price per share \| $ / shares					$ 1.10
Proceeds from issuance of redeemable convertible preferred stock before issuance cost					$ 11,000,000
Preferred stock redemption premium					$ 478,000
Preferred stock, accretion of redemption discount												$ 26,000		5,000	$ 31,000	10,000
Preferred stock, value, outstanding																	$ 33,686,000
Preferred stock, share, outstanding \| shares																	22,608,695
Series B Redeemable convertible Preferred Stock Member [Member] \| Common Stock [Member]
Temporary Equity [Line Items]
Unaccreted premium												$ 22,000			$ 22,000
Series B Redeemable convertible Preferred Stock Member [Member] \| Series B Purchase Agreement [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares						13,043,478
Adjustments to additional paid in capital, stock issued, issuance costs						$ 56,000
Proceeds from issuance of redeemable convertible preferred stock						$ 15,000,000
Shares issued, price per share \| $ / shares						$ 1.15
Series B Redeemable convertible Preferred Stock Member [Member] \| Series B Second Closing [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares					8,695,652
Share price \| $ / shares					$ 1.15
Series C Redeemable convertible Preferred Stock Member [Member]
Temporary Equity [Line Items]
Preferred Stock, Shares Authorized \| shares																	48,200,412
Share price \| $ / shares												$ 1.46			$ 1.46
Preferred stock, value, outstanding																	$ 61,023,000
Preferred stock, share, outstanding \| shares																	38,097,672
Series C Redeemable convertible Preferred Stock Member [Member] \| IPO [Member]
Temporary Equity [Line Items]
Preferred stock, share, outstanding \| shares												0			0
Series C Redeemable convertible Preferred Stock Member [Member] \| Tranche One [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares			101,707	20,547,946
Adjustments to additional paid in capital, stock issued, issuance costs			$ 19,000	$ 291,000
Proceeds from issuance of redeemable convertible preferred stock			$ 129,000	$ 29,700,000
Shares issued, price per share \| $ / shares			$ 1.46	$ 1.46
Stock issued during period, value, new issues				$ 50,500,000
Number of additional investors \| Investor			2
Series C Redeemable convertible Preferred Stock Member [Member] \| Tranche Two [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares		55,621								7,211,165
Adjustments to additional paid in capital, stock issued, issuance costs										$ 32,000
Proceeds from issuance of redeemable convertible preferred stock		$ 81,000								$ 10,500,000
Shares issued, price per share \| $ / shares		$ 1.46								$ 1.46
Series C Redeemable convertible Preferred Stock Member [Member] \| Tranche Third [Member]
Temporary Equity [Line Items]
Stock issued during period, shares, new issues \| shares									6,849,315
Adjustments to additional paid in capital, stock issued, issuance costs									$ 37,000
Proceeds from issuance of redeemable convertible preferred stock									$ 10,000,000
Shares issued, price per share \| $ / shares									$ 1.46
Preferred stock value outstanding at fair value																	$ 2,100
Series C Preferred Stock [Member]
Temporary Equity [Line Items]
Shares issued, price per share \| $ / shares												$ 1.46			$ 1.46
Percentage of preferred shareholders remaining outstanding												66.67%			66.67%
Fair value of preferred stock share price \| $ / shares																		$ 1.44
Payments of financing costs												$ 379,000		379,000
Accretion of financing costs												188,000		26,000	$ 223,000	52,000
Series C Preferred Stock [Member] \| Measeurement Input, Discount for Lack of Marketability [Member]
Temporary Equity [Line Items]
Fair value estimates of common stock discount rate																	1.44
Series C Preferred Stock [Member] \| Tranche One [Member] \| Convertible Debt [Member]
Temporary Equity [Line Items]
Debt instrument, convertible, conversion price \| $ / shares				$ 1.095
Debt instrument, face amount				$ 10,600,000
Accrued interest on debt				$ 564,000
Debt instrument, convertible, number of equity instruments \| shares				10,181,233
Series C Preferred Stock [Member] \| Tranche Two [Member] \| Restatement Adjustment [Member]
Temporary Equity [Line Items]
Preferred stock value outstanding at fair value																	$ 1,000
Series C Preferred Stock [Member] \| Tranche Third [Member]
Temporary Equity [Line Items]
Preferred stock, value, outstanding									$ 1,100,000
Series C Preferred Stock [Member] \| Tranche Third [Member] \| Restatement Adjustment [Member]
Temporary Equity [Line Items]
Preferred stock value outstanding at fair value																	1,100
Series C Preferred Stock [Member] \| Common Stock [Member]
Temporary Equity [Line Items]
Unaccreted financing costs												$ 164,000			$ 164,000
Series A Preferred Stock [Member]
Temporary Equity [Line Items]
Proceeds from issuance of redeemable convertible preferred stock													$ 2,800,000
Shares issued, price per share \| $ / shares												$ 1.00			$ 1.00
Percentage of preferred shareholders remaining outstanding												60.00%			60.00%
Payments of financing costs																	$ 166,000
Accretion of financing costs													6,000	1,000	$ 7,000	2,000
Fair value adjustment on preferred stock value													$ 520,000
Accretion of investor rights												$ 70,000		13,000	$ 84,000	27,000
Percentage conversion of preferred stock outstanding															60.00%
Series A Preferred Stock [Member] \| Measeurement Input, Discount for Lack of Marketability [Member]
Temporary Equity [Line Items]
Fair value estimates of common stock discount rate																	0.82
Series A Preferred Stock [Member] \| Common Stock [Member]
Temporary Equity [Line Items]
Unaccreted financing costs												5,000			$ 5,000
Unaccreted investor rights												$ 61,000			$ 61,000
Series B Preferred Stock [Member]
Temporary Equity [Line Items]
Shares issued, price per share \| $ / shares												$ 1.15			$ 1.15
Percentage of preferred shareholders remaining outstanding												60.00%			60.00%
Payments of financing costs																			$ 76,000
Accretion of financing costs												$ 3,000		1,000	$ 4,000	1,000
Accretion of investor rights												98,000		$ 19,000	38,000	$ 117,000
Proceeds from series A preferred stock financing															$ 2,000,000
Percentage conversion of preferred stock outstanding															60.00%
Series B Preferred Stock [Member] \| Measeurement Input, Discount for Lack of Marketability [Member]
Temporary Equity [Line Items]
Fair value estimates of common stock discount rate																	0.86
Series B Preferred Stock [Member] \| Common Stock [Member]
Temporary Equity [Line Items]
Unaccreted financing costs												3,000			$ 3,000
Unaccreted investor rights												$ 85,000			$ 85,000

Redeemable Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Preferred Shares Authorized	5,000,000	0
Preferred Shares Issued	0	0
Preferred Shares Outstanding	0	0
Common Shares Issuable Upon Conversion	2,778,812	10,690,261
Series A Redeemable convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		15,387,923
Preferred Shares Issued		15,387,923
Preferred Shares Outstanding		15,387,923
Carrying Value		$ 21,033
Liquidation Preference		$ 20,469
Common Shares Issuable Upon Conversion		2,154,572
Series B Redeemable convertible Preferred Stock Member [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		22,608,695
Preferred Shares Issued		22,608,695
Preferred Shares Outstanding		22,608,695
Carrying Value		$ 33,686
Liquidation Preference		$ 32,900
Common Shares Issuable Upon Conversion		3,011,392
Series C Redeemable convertible Preferred Stock Member [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		48,200,412
Preferred Shares Issued		38,097,672
Preferred Shares Outstanding		38,097,672
Carrying Value		$ 61,023
Liquidation Preference		$ 59,798
Common Shares Issuable Upon Conversion		4,311,279
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Shares Authorized		86,197,030
Preferred Shares Issued		76,094,290
Preferred Shares Outstanding		76,094,290
Carrying Value		$ 115,742
Liquidation Preference		$ 113,167
Common Shares Issuable Upon Conversion		9,477,243

Stock-Based Awards - Additional Information (Detail) - shares	1 Months Ended		3 Months Ended	6 Months Ended
	Apr. 30, 2019	May 30, 2018	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance			2,778,812	2,778,812		10,690,261
Share based compensation options to purchase no of common stock			1,688,177	1,688,177		1,077,148
Share based compensation options grants in the period				667,102
Share based compensation options exercise in the period				14,736
Share based compensation options forfeited in the period				35,745
Share based compensation options expired in the period				5,592
Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options exercise in the period			6,842	14,736	5,679
2019 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, award description				Awards may be made under the 2019 Plan for up to such number of shares of the Company’s common stock as is equal to the sum of: i) 1,578,947 shares; plus ii) the number of shares (up to 1,157,894 shares) equal to the number of shares of the Company’s common stock subject to outstanding awards under the 2012 Plan that expire, terminate or are otherwise cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right; plus iii) an annual increase to be added on the first day of each fiscal year, beginning with 2020 and continuing through 2029, equal to the least of (a) 2,105,623 shares of common stock, (b) 4% of the number of outstanding shares of the Company’s common stock on such date, and (c) an amount determined by the Company’s board of directors.
Common stock, capital shares reserved for future issuance	1,578,947
2019 Stock Incentive Plan [Member] \| Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in additional number of shares to be issued	2,105,623
Percentage of number of common stock, shares outstanding	4.00%
2012 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options to purchase no of common stock			1,044,759	1,044,759		1,077,148
Share based compensation grant period		10 years
Share based compensation vesting period		4 years
Share based compensation vesting description				Options vest over four years based on varying vesting schedules including: 25% vesting on the first anniversary date of grant and the balance ratably over the next 36 months or vesting in equal monthly or quarterly installments over four years.
Share based compensation options grants in the period					146,103
Share based compensation options exercise in the period					5,679
Share based compensation options forfeited in the period					0
Share based compensation options expired in the period					0
2012 Stock Incentive Plan [Member] \| Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period	0
2012 Stock Incentive Plan [Member] \| Other Equity-Based Award [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period	0
2012 Stock Incentive Plan [Member] \| Vesting First Anniversary Date of Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting Percentage		25.00%
2012 Stock Incentive Plan [Member] \| Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options to purchase no of common stock	1,157,894
2019 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, award description				The number of shares of the Company’s common stock that have been approved to be issued under the 2019 ESPP is equal to the sum of: i) 155,106 shares; plus ii) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2020 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2029, equal to the least of (a) 526,315 shares of common stock, (b) 1% of the number of outstanding shares of the Company’s common stock on such date, and (c) an amount determined by the Company’s board of directors.
Common stock, capital shares reserved for future issuance	155,106
2019 Employee Stock Purchase Plan [Member] \| Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in additional number of shares to be issued	526,315
Percentage of number of common stock, shares outstanding	1.00%

Stock-Based Awards - Stock Options, Activity (Detail) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares
Number of Option Shares
Outstanding, Beginning \| shares	1,077,148
Granted \| shares	667,102
Forfeited \| shares	(35,745)
Expired \| shares	(5,592)
Exercised \| shares	(14,736)
Outstanding, Ending \| shares	1,688,177	1,077,148
Options exercisable \| shares	592,456
Options unvested \| shares	1,095,721
Weighted Average Exercise Price
Outstanding, Beginning \| $ / shares	$ 3.90
Granted \| $ / shares	10.09
Forfeited \| $ / shares	7.67
Expired \| $ / shares	3.04
Exercised \| $ / shares	2.60
Outstanding, Ending \| $ / shares	6.26	$ 3.90
Options exercisable \| $ / shares	2.69
Options unvested \| $ / shares	$ 8.19
Weighted Average Contractual Term, Outstanding	8 years 3 months 18 days	7 years 9 months 18 days
Weighted Average Contractual Term, Options exercisable	5 years 7 months 6 days
Weighted Average Contractual Term, Options unvested	9 years 4 months 24 days
Aggregate Intrinsic Value, Outstanding \| $	$ 3,946	$ 5,857
Aggregate Intrinsic Value, Options exercisable \| $	2,853
Aggregate Intrinsic Value, Options unvested \| $	$ 1,093

Stock-Based Awards - Stock-based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock-based compensation	$ 237	$ 102	$ 383	$ 190
Research and Development Expense [Member]
Stock-based compensation	30	39	52	75
General and Administrative Expense [Member]
Stock-based compensation	$ 207	$ 63	$ 331	$ 115

Net Loss per Share - Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (7,346)	$ (4,858)	$ (12,148)	$ (8,909)	$ (20,500)
Plus: Dividends accrued on redeemable convertible preferred stock	(1,332)	(175)	(1,535)	(370)
Plus: Accretion of redeemable convertible preferred stock	(686)	(1,293)	(2,239)	(2,573)
Adjusted net loss attributable to common stockholders	$ (6,700)	$ (5,976)	$ (12,852)	$ (11,112)
Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted	10,571,736	438,606	5,535,907	436,598
Basic and diluted net loss per common share outstanding	$ (0.63)	$ (13.62)	$ (2.32)	$ (25.45)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net Loss per Share - Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Antidilutive securities excluded from computation of earnings per share, amount	1,688,177	69,866,974
Series A Redeemable convertible Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share, amount		15,387,923
Series B Redeemable convertible Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share, amount		22,608,695
Series C Redeemable convertible Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share, amount		30,886,507
Stock Option [Member]
Antidilutive securities excluded from computation of earnings per share, amount	1,688,177	983,849

Collaborative and Licensing Agreements - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Endo Pharmaceuticals Inc [Member]
Upfront license fee	$ 25
Royalty terms	first commercial sale of the product in that country and extends until the later of the expiration, unenforceability or invalidation of the last valid claim of any licensed patent or application covering the licensed product in the country or the expiration of 10 years after the first commercial sale of the licensed product in the country, which period is referred to as the royalty term. Upon the expiration of the royalty term for a product in a country
Endo Pharmaceuticals Inc [Member] \| Completion Of Stage One [Member]
Milestone payment	$ 250
Endo Pharmaceuticals Inc [Member] \| Completion Of Stage Two [Member]
Milestone payment	750
Rutgers [Member]
Milestone payment	$ 331
Royalty terms	first commercial sale of the licensed product in that country following receipt of marketing approval and extends until the later of the date of expiration, unenforceability or invalidation of the last valid claim of any licensed patent or patent application covering the licensed product in the country and 10 years after the first commercial sale of the first licensed product sold anywhere in the world, which period is referred to as the royalty term. Upon the expiration of the royalty term for a licensed product in a country, the license granted to the Company under the agreement shall become perpetual, fully paid-up, irrevocable and royalty-free in such country
MentiNova Inc [Member]
Upfront license fee	$ 119
MentiNova Inc [Member] \| Completion Of Stage One [Member]
Milestone payment	$ 1,188