Trevi Therapeutics (TRVI) 10-Q 11 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 11, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
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		42,770,577
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	45-0834299
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	CT
Entity Address, Postal Zip Code	06510
City Area Code	203
Local Phone Number	304-2499
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 24,698	$ 36,830
Marketable securities	53,157
Prepaid expenses	1,648	886
Other current assets	382	241
Total current assets	79,885	37,957
Marketable securities - non-current	1,000
Other non-current assets	413	334
Operating lease right-of-use asset	82	131
Property, equipment and leasehold improvements, net	34	53
Total assets	81,414	38,475
Current liabilities:
Accounts payable	3,938	2,849
Accrued expenses	4,403	3,808
Term loan	7,000	5,833
Term loan derivative liability		114
Operating lease liability	92	120
Total current liabilities	15,433	12,724
Term loan	5,428	8,652
Operating lease liability	3	24
Other non-current liabilities	35
Total liabilities	20,899	21,400
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock: $0.001 par value; 5,000,000 shares authorized at June 30, 2022 and December 31, 2021; no shares issued or outstanding at June 30, 2022 and December 31, 2021.
Common stock: $0.001 par value; 200,000,000 shares authorized at June 30, 2022 and December 31, 2021; and 39,719,572 and 28,505,804 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively.	40	29
Additional paid-in capital	256,908	197,963
Accumulated other comprehensive loss	(135)
Accumulated deficit	(196,298)	(180,917)
Total stockholders’ equity	60,515	17,075
Total liabilities and stockholders’ equity	$ 81,414	$ 38,475

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	39,719,572	28,505,804
Common Stock, Shares, Outstanding	39,719,572	28,505,804

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating expenses:
Research and development	$ 5,103	$ 6,498	$ 9,748	$ 12,087
General and administrative	2,717	2,669	5,097	5,169
Total operating expenses	7,820	9,167	14,845	17,256
Loss from operations	(7,820)	(9,167)	(14,845)	(17,256)
Other (expense) income:
Change in fair value of term loan derivative liability	(136)	40	(147)	34
Other expense		(375)		(375)
Interest income, net	195	2	199	5
Interest expense	(295)	(296)	(597)	(590)
Total other expense, net	(236)	(629)	(545)	(926)
Loss before income taxes	(8,056)	(9,796)	(15,390)	(18,182)
Income tax benefit	4	2	9	17
Net loss	$ (8,052)	$ (9,794)	$ (15,381)	$ (18,165)
Basic net loss per common share outstanding	$ (0.14)	$ (0.49)	$ (0.34)	$ (0.92)
Diluted net loss per common share outstanding	$ (0.14)	$ (0.49)	$ (0.34)	$ (0.92)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	59,542,628	20,123,461	45,253,599	19,772,201
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	59,542,628	20,123,461	45,253,599	19,772,201
Net loss	$ (8,052)	$ (9,794)	$ (15,381)	$ (18,165)
Other comprehensive loss:
Net unrealized losses on available-for-sale marketable securities	(135)		(135)
Comprehensive loss	$ (8,187)	$ (9,794)	$ (15,516)	$ (18,165)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Lincoln Park Capital Fund, LLC [Member]	At-the-Market Sales Agreement [Member]	Private Placement [Member]	Common Stock [Member]	Common Stock [Member] Lincoln Park Capital Fund, LLC [Member]	Common Stock [Member] At-the-Market Sales Agreement [Member]	Common Stock [Member] Private Placement [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Lincoln Park Capital Fund, LLC [Member]	Additional Paid-in Capital [Member] At-the-Market Sales Agreement [Member]	Additional Paid-in Capital [Member] Private Placement [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2020	$ 27,282				$ 19				$ 174,240					$ (146,977)
Beginning Balance (in shares) at Dec. 31, 2020					18,546,786
Stock-based compensation	1,463								1,463
Issuance of common stock, net of commissions and allocated fees, less issuance costs			$ 6,764				$ 2				$ 6,762
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)							2,733,492
Issuance of common stock from Employee Stock Purchase Plan	17								17
Issuance of common stock from employee stock purchase plan (in shares)					9,132
Issuance of common stock to Lincoln Park Capital Fund		$ 375								$ 375
Issuance of common stock to Lincoln Park Capital Fund (in shares)						170,088
Net loss	(18,165)													(18,165)
Ending Balance at Jun. 30, 2021	17,736				$ 21				182,857					(165,142)
Ending Balance (in shares) at Jun. 30, 2021					21,459,498
Beginning Balance at Mar. 31, 2021	23,685				$ 20				179,013					(155,348)
Beginning Balance (in shares) at Mar. 31, 2021					19,914,407
Stock-based compensation	745								745
Issuance of common stock, net of commissions and allocated fees, less issuance costs			2,708				$ 1				2,707
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)							1,365,871
Issuance of common stock from Employee Stock Purchase Plan	17								17
Issuance of common stock from employee stock purchase plan (in shares)					9,132
Issuance of common stock to Lincoln Park Capital Fund		$ 375								$ 375
Issuance of common stock to Lincoln Park Capital Fund (in shares)						170,088
Net loss	(9,794)													(9,794)
Ending Balance at Jun. 30, 2021	17,736				$ 21				182,857					(165,142)
Ending Balance (in shares) at Jun. 30, 2021					21,459,498
Beginning Balance at Dec. 31, 2021	17,075				$ 29				197,963					(180,917)
Beginning Balance (in shares) at Dec. 31, 2021					28,505,804
Stock-based compensation	1,257								1,257
Issuance of common stock, net of commissions and allocated fees, less issuance costs			(42)	$ 51,826				$ 5			(42)	$ 51,821
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)								4,580,526
Issuance of common stock from Employee Stock Purchase Plan	23								23
Issuance of common stock from employee stock purchase plan (in shares)					33,972
Issuance of common stock from warrant exercise	5,892				$ 6				5,886
Issuance of common stock from warrant exercise (in shares)					6,599,270
Unrealized losses on available-for-sale marketable securities	(135)												$ (135)
Net loss	(15,381)													(15,381)
Ending Balance at Jun. 30, 2022	60,515				$ 40				256,908				(135)	(196,298)
Ending Balance (in shares) at Jun. 30, 2022					39,719,572
Beginning Balance at Mar. 31, 2022	10,463				$ 31				198,678					(188,246)
Beginning Balance (in shares) at Mar. 31, 2022					30,805,804
Stock-based compensation	520								520
Issuance of common stock, net of commissions and allocated fees, less issuance costs			$ (20)	$ 51,826				$ 5			$ (20)	$ 51,821
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)								4,580,526
Issuance of common stock from Employee Stock Purchase Plan	23								23
Issuance of common stock from employee stock purchase plan (in shares)					33,972
Issuance of common stock from warrant exercise	5,890				$ 4				5,886
Issuance of common stock from warrant exercise (in shares)					4,299,270
Unrealized losses on available-for-sale marketable securities	(135)												(135)
Net loss	(8,052)													(8,052)
Ending Balance at Jun. 30, 2022	$ 60,515				$ 40				$ 256,908				$ (135)	$ (196,298)
Ending Balance (in shares) at Jun. 30, 2022					39,719,572

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net loss	$ (15,381)	$ (18,165)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	19	25
Accretion of available-for-sale marketable securities, net	(72)
Change in fair value of term loan derivative liability	147	(34)
Accretion/accrual of term loan discounts and debt issuance costs	297	291
Other expense related to transaction with Lincoln Park Capital Fund, LLC		375
Stock-based compensation	1,257	1,463
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(885)	(592)
Accounts payable	941	1,471
Accrued expenses and other liabilities	409	(310)
Net cash used in operating activities	(13,268)	(15,476)
Investing activities:
Purchases of available-for-sale marketable securities	(54,217)
Net cash used in investing activities	(54,217)
Financing activities:
Repayments of term loan	(2,333)
Payments of financing costs of term loan	(21)
Proceeds from sale of common stock and warrants under private placement, net of issuance costs	51,826
Proceeds from exercises of warrants	5,892
Proceeds from employee stock purchase plan	23	17
Proceeds from at-the-market sales, net of commissions		6,972
Payments of offering costs	(34)	(89)
Net cash provided by financing activities	55,353	6,900
Net decrease in cash and cash equivalents	(12,132)	(8,576)
Cash and cash equivalents at beginning of period	36,830	45,001
Cash and cash equivalents at end of period	$ 24,698	$ 36,425

Nature of the Business

Nature of the Business	6 Months Ended
	Jun. 30, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business	1. Trevi Therapeutics, Inc. (“Trevi” or the “Company”) is a clinical-stage biopharmaceutical company focused on the development and commercialization of the investigational therapy Haduvio (oral nalbuphine ER) to treat serious neurologically mediated conditions. The Company is currently developing Haduvio for the treatment of prurigo nodularis and chronic cough in adults with idiopathic pulmonary fibrosis (“IPF”). 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 Haduvio has the potential to be effective in treating each of these conditions. Haduvio 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 the United States (“U.S.”) 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. Parenteral nalbuphine is not scheduled as a controlled substance in the U.S. and most of Europe.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Basis of Presentation The accompanying unaudited interim Condensed Consolidated Financial Statements for the three and six months ended June 30, 2022 and 2021 included herein have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim information. Certain information and footnote disclosures 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 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 (the “Annual Report on Form 10-K”). 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, 2022 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 in Note 13. 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, the valuation of stock-based awards and the valuation allowance of deferred tax assets resulting from net operating losses. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. The inputs into the Company’s estimates also considered the economic implications of the COVID-19 pandemic on the Company’s estimates. Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheet as of June 30, 2022 and the Condensed Consolidated Statements of Comprehensive Loss, the Condensed Consolidated Statements of Stockholders’ Equity and the Condensed Consolidated Statements of Cash Flows for the three and six months ended June 30, 2022 and 2021 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, 2022 and the results of its operations and its cash flows for the three and six months ended June 30, 2022 and 2021. The results for the three and six months ended June 30, 2022 and 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2022 or any other interim period or any future year or period. Cash Equivalents The Company classifies short-term, highly liquid investments with an original term of three months or less at the date of purchase as cash equivalents. Marketable Securities The Company generally invests its excess cash in money market funds and investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term marketable securities or long-term marketable securities on the Condensed Consolidated Balance Sheet. Marketable securities with an original maturity date greater than 90 days and less than one year at each balance sheet date are classified as short-term. Marketable securities with a maturity date greater than one year at each balance sheet date are classified as long-term. All of the Company’s marketable securities are considered available-for-sale and are reported at fair value with unrealized gains and losses included as a component of stockholders’ equity (deficit). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on marketable securities are included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. The cost of securities sold is determined using specific identification. The Company evaluates whether declines in the fair values of its marketable securities below their amortized cost are other-than temporary on a quarterly basis. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the marketable security or whether it is more likely than not that it will be required to sell any marketable securities before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the marketable security. Fair Value Measurements The Company’s financial instruments have consisted of cash and cash equivalents, available-for-sale marketable securities, other current assets, accounts payable, accrued expenses, term loans, term loan derivative liability and warrants to acquire the Company’s common stock. Fair instruments. Available-for-sale marketable securities are reported at their fair values, based upon pricing of securities with the same or similar investment characteristics as provided by third-party pricing services, as described below. The fair value of the term loan derivative liability is estimated utilizing a probability-weighted cash flow approach. The warrants to acquire the Company’s common stock are not required to be accounted for at fair value. 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, 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. Valuation Techniques - Level 2 Inputs The Company estimates the fair values of its financial instruments categorized as level 2 in the fair value hierarchy, including U.S. Treasury securities, U.S. government agency obligations, corporate bonds, commercial paper and municipal bonds, by taking into consideration valuations obtained from third-party pricing services. The pricing services use industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, benchmark yields, issuer credit spreads, benchmark securities, and other observable inputs. The Company obtains a single price for each financial instrument and does not adjust the prices obtained from the pricing service. Property, Equipment and Leasehold Improvements Property, equipment and leasehold improvements (consisting of furniture, computer and office equipment and leasehold improvements) are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the respective assets (three years for computer equipment, five years for furniture and office equipment and the shorter of the term of the lease or useful life for leasehold improvements). Impairment of Long-Lived Assets ASC 360, Property, Plant and Equipment, Foreign Currency Transactions The Company, at times, contracts with vendors and consultants outside of the U.S., resulting in liabilities denominated in foreign currency. The transactions are recorded in U.S. dollars on the transaction dates and any currency fluctuation through the payment date is recorded as currency gains or losses in the Condensed Consolidated Statements of Comprehensive Loss. 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 as a reduction of additional paid-in capital generated as a result of the financings. 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. The deferred offering costs are included in Other non-current assets on the Condensed Consolidated Balance Sheets. Research and Development (“R&D”) Expenses All of the Company’s R&D expenses consist of expenses incurred in connection with the development of Haduvio. These expenses include certain payroll and personnel expenses, including stock-based compensation, consulting costs, contract manufacturing costs and fees paid to clinical research organizations (“CROs”) to conduct certain R&D activities on the Company’s behalf. The Company does not allocate its costs by each indication for which it is developing Haduvio, as a significant amount of the Company’s development activities broadly support all indications. In addition, several of the Company’s departments support the Company’s Haduvio drug candidate development program and the Company does not identify internal costs for each potential indication. The Company expenses both internal and external R&D expenses as they are incurred. Accrued R&D Expenses The Company has entered into agreements with CROs, contract manufacturing organizations (“CMOs”) and other companies that provide services in connection with the Company’s R&D activities. The Company’s R&D accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events and contracted costs. The estimated costs of R&D provided, but not yet invoiced, are included in accrued expenses on the Condensed Consolidated Balance Sheets. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CROs, CMOs and other companies under these arrangements in advance of the performance of the related services are recorded as prepaid expenses or as other non-current assets, as applicable, and are recognized as expenses as the goods are delivered or the related services are performed. Patent Costs All patent-related costs in connection with filing and prosecuting patent applications are expensed to general and administrative expense as incurred, as recoverability of such expenditures is uncertain. Warrants The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging If warrants do not meet liability classification under ASC 480, the Company assesses the requirements under ASC 815, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815, in order to conclude equity classification, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815 or other applicable GAAP. After all relevant assessments are made, the Company concludes whether the warrants are classified as liability or equity. Liability classified warrants are required to be accounted for at fair value both on the date of issuance and on subsequent accounting period ending dates, with all changes in fair value after the issuance date recorded in the statements of comprehensive loss as a gain or loss. For equity classified warrants, no changes in fair value are recognized after the issuance date. Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employees for consultancy services in accordance with ASC 718, Stock Compensation Changes in the variables can materially affect the fair value and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require analysis and judgment to develop. Expected Term—The expected term assumption represents the weighted average period that the stock-based awards are expected to be outstanding. The Company has elected to use the “simplified method” for estimating the expected term of its stock options, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the stock option. Expected Volatility—For all stock options granted to date, the volatility data was estimated based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. Expected Dividend—The Black-Scholes valuation model calls for a single expected dividend yield as an input. The Company currently has no history or expectation of paying cash dividends on its common stock. Risk-Free Interest Rate—The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the stock-based award. The fair value is recognized over the period during which an optionee is required to provide services in exchange for the stock option, known as the requisite service period (usually the vesting period) on a straight-line basis. For performance-based vesting, the fair value is recognized when the performance conditions are probable. The Company reassesses the probability of achieving the performance conditions at each reporting date. Forfeitures are accounted for as they occur. Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Deferred income tax assets are reduced, as necessary, by a valuation allowance when management determines it is more likely than not that some or all of the tax benefits will not be realized. The Company applies the provisions of ASC 740, Income Taxes Leases Under ASC 842, Leases 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. Basic and Diluted Net Income (Loss) per Common Share Basic and diluted net loss per common share outstanding is determined by dividing net loss by the weighted average common shares outstanding during the period. Basic shares outstanding includes the weighted average effect of the Company’s outstanding pre-funded warrants, the exercise of which requires little or no consideration for the delivery of shares of common stock. For all periods presented, shares issuable upon exercise of stock options and warrants to purchase shares of common stock (other than pre-funded warrants) 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 each of the periods presented. Segments The Company has one reporting segment which is also the Company’s only operating segment. Management uses one measurement of profitability and does not segregate its business for internal reporting. All long-lived assets are maintained in the U.S. Recently Adopted Accounting Pronouncements There have been no new pronouncements adopted during the six months ended June 30, 2022, which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the six months ended June 30, 2022, which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements.

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2022
Investments Debt And Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities The fair value and amortized cost of available-for-sale marketable securities by major security type as of June 30, 2022 are presented in the following table (in thousands): June 30, 2022 Type of security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury securities $ 19,785 $ — $ (45 ) $ 19,740 Corporate bonds 15,485 — (90 ) 15,395 Commercial paper 19,022 — — 19,022 Total marketable securities $ 54,292 $ — $ (135 ) $ 54,157 As of June 30, 2022, the remaining contractual maturities of available-for-sale marketable securities were as follows (in thousands): June 30, 2022 Amortized Cost Fair Value Due to mature: Less than one year $ 53,283 $ 53,157 One year through two years 1,009 1,000 Total $ 54,292 $ 54,157 During the three and six months ended June 30, 2022, there have been no realized gains or losses on available-for-sale marketable securities, no marketable securities had been in a continuous unrealized loss position for more than 12 months, and the Company did not recognize any other-than-temporary impairment losses on these marketable securities.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4 . Fair Value Measurements The following table summarizes the financial assets and financial liabilities measured at fair value on a recurring basis as of June 30, 2022 and December 31, 2021, and the basis for that measurement, by level within the fair value hierarchy: Fair Value Measurement Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total June 30, 2022 Financial assets: Cash equivalents Money market funds $ 21,699 $ — $ — $ 21,699 Cash equivalents Corporate bonds — 1,999 — 1,999 Marketable securities U.S. treasury securities 19,740 — — 19,740 Marketable securities Corporate bonds — 15,395 — 15,395 Marketable securities Commercial paper — 19,022 — 19,022 Total assets $ 41,439 $ 36,416 $ — $ 77,855 Fair Value Measurement Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total December 31, 2021 Financial assets: Cash equivalents Money market funds $ 35,835 $ — $ — $ 35,835 Total assets $ 35,835 $ — $ — $ 35,835 Financial liabilities: Term loan derivative liability $ — $ — $ 114 $ 114 Total liabilities $ — $ — $ 114 $ 114 The following table represents a roll-forward of the fair value of Level 3 instruments (significant unobservable inputs): June 30, 2022 December 31, 2021 Financial liabilities Balance at beginning of period $ 114 $ 196 Change in fair value of term loan derivative liability 147 (82 ) Net settlements (see Note 7) (261 ) — Balance at end of period $ — $ 114

Leases

Leases	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Leases	5 . 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 (collectively, the “Office Space Lease”). The leased space approximates 5,600 square feet and the Office Space Lease has a term of 60 months. The Office Space Lease requires monthly payments ranging from approximately $10 to $12 through February 1, 2023 and provides for two designated months of free rent. The Company also entered into an immaterial office equipment lease during the three months ended June 30, 2022 that has a term of 36 months. The incremental borrowing rate used on the Office Space Lease 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 significant new leases during the six months ended June 30, 2022. The Office Space Lease is an operating lease and the remaining term as of June 30, 2022 is approximately 0.8 years June 30, 2022 December 31, 2021 Assets: Operating lease right-of-use asset $ 82 $ 131 Liabilities: Operating lease liabilities, current portion 92 120 Operating lease liabilities, long term portion 3 24 Total operating lease liabilities $ 95 $ 144 Future minimum lease payments from June 30, 2022 until the expiration of the operating leases are as follows: 2022 $ 72 2023 25 2024 2 2025 1 Total lease payments 100 Less: imputed discount rate (5 ) Carrying value of operating lease liabilities $ 95 Lease expense under operating leases, including leases of office equipment, was $23 and $30 for the three months ended June 30, 2022 and 2021, respectively, and $61 and $61 for the six months ended June 30, 2022 and 2021, respectively. Lease payments made in the three months ended June 30, 2022 and 2021 were $24 and $35, respectively, and $59 and $69 for the six months ended June 30, 2022 and 2021, respectively, with such amounts reflected in the Condensed Consolidated Statements of Cash Flows in operating activities.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2022
Payables And Accruals [Abstract]
Accrued Expenses	6 . Accrued Expenses Accrued expenses consisted of the following: June 30, 2022 December 31, 2021 Accrued R&D projects $ 2,567 $ 2,303 Accrued compensation and benefits 1,054 1,250 Accrued consulting and professional fees 450 176 Accrued other 332 79 Total accrued expenses $ 4,403 $ 3,808

Debt

Debt	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Debt	7 . Debt Silicon Valley Bank Term Loan On August 13, 2020 (the “Effective Date”), the Company entered into a loan and security agreement (the “SVB Loan Agreement”) with Silicon Valley Bank, as lender (“SVB”), pursuant to which SVB provided a term loan to the Company in the original principal amount of $14.0 million (the “SVB Term Loan”). The SVB Term Loan bears interest at a floating rate per annum equal to the greater of (A) the prime rate plus 1.00% and (B) 4.25%. If SVB received evidence satisfactory to it that the Company had (i) received positive data for the Phase 2b/3 clinical trial of Haduvio sufficient to advance Haduvio into a second Phase 3 clinical trial for prurigo nodularis, and (ii) raised sufficient financing to fund such Phase 3 clinical trial and the Company’s operations, (together, the “Phase 3 Event”), the interest rate under the SVB Term Loan would have been adjusted to a floating rate equal to the greater of (A) the prime rate plus 3.00% and (B) 6.25% (see term loan derivative liability discussion below). Commencing on March 1, 2022 and on the first business day of each month thereafter, the Company is required to make monthly interest payments and the Company will be required to repay the SVB Term Loan in 24 consecutive installments of principal plus monthly payments of accrued interest. All outstanding principal and accrued and unpaid interest under the SVB Term Loan and all other outstanding obligations with respect to the SVB Term Loan are due and payable in full on February 1, 2024. The SVB Loan Agreement permits voluntary prepayment of all, but not less than all, of the SVB Term Loan, subject to a prepayment premium. Such prepayment premium would be 3.00% of the principal amount of the SVB Term Loan if prepaid prior to the first anniversary of the Effective Date, 2.00% of the principal amount of the SVB Term Loan if prepaid on or after the first anniversary of the Effective Date but prior to the second anniversary of the Effective Date, and 1.00% of the principal amount of the SVB Term Loan if prepaid on or after the second anniversary of the Effective Date but prior to February 1, 2024. Upon repayment in full of the SVB Term Loan, the Company will be required to pay a final payment fee equal to $1.2 million. The SVB Term Loan and related obligations under the SVB Loan Agreement are secured by substantially all of the Company’s properties, rights and assets, except for its intellectual property (which is subject to a negative pledge under the SVB Loan Agreement). On July 6, 2021, the Company and SVB entered into a First Amendment (the “Loan Amendment”) to the SVB Loan Agreement. The Loan Amendment modified the conditions under which the Company was required to cash collateralize all outstanding amounts owed to SVB under the . Under the to raise by June 30, 2022 sufficient net proceeds from the sale of equity securities to finance its planned second Phase 3 clinical trial of Haduvio for prurigo nodularis and its ongoing operations (each a “Milestone Condition”), the Company would be required to deposit unrestricted and unencumbered cash equal to 100% of all outstanding amounts owed to SVB in a cash collateral account with SVB, which could be used by SVB to prepay the SVB Term Loan at any time. Agreement . The Company would also have been required to cash collateralize all outstanding amounts owed to SVB under the SVB Loan Agreement if it did not raise at least $ 15.0 million in net proceeds from the sale of equity securities during the period from June 1, 2021 through October 31, 2021. The Company satisfied this equity funding condition through a combination of equity issuances under the Company’s ATM Sales Agreement and two private placements, which took place in October 2021 (see Note 8 ). On April 6, 2022, the Company and SVB entered into a Third Amendment (the “Third Amendment”) to the SVB Loan Agreement SVB Loan Agreement The SVB Loan Agreement contains customary representations, warranties, events of default and covenants. The occurrence and continuation of an event of default could cause interest to be charged at the rate that is otherwise applicable plus 5.00% (unless SVB elects to impose a smaller increase) and would provide SVB with the right to accelerate all obligations under the SVB Loan Agreement and exercise remedies against the Company and the collateral securing the SVB Term Loan and other obligations under the SVB Loan Agreement, including foreclosure against assets securing the SVB Term Loan and other obligations under the SVB Loan Agreement, including the Company’s cash. The SVB Loan Agreement also restricts the payment of dividends on the Company’s common stock. In August 2020, in connection with the SVB Term Loan, the Company paid $57 in financing costs to a third party, which were recorded as deferred charges and will be amortized over the life of the SVB Term Loan using the effective interest method. In connection with the Loan Amendment, the Company paid $68 in financing costs to a third party, which were recorded as deferred charges and will be amortized over the remaining life of the SVB Term Loan using the effective interest method. In connection with the Third Amendment, the Company paid $21 in financing costs to a third party, which were recorded as deferred charges and will be amortized over the remaining life of the SVB Term Loan using the effective interest method. Amortization of these deferred financing charges totaled $20 and $5 for the three months ended June 30, 2022 and 2021, respectively, and $37 and $11 for the six months ended June 30, 2022 and 2021, respectively, and is included in interest expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss. The unamortized deferred charges totaled $60 and $76 at June 30, 2022 and December 31, 2021, respectively, and are included as a direct reduction of the carrying value of the term loan payable on the Company’s Condensed Consolidated Balance Sheets. In August 2020, in connection with the execution of the SVB Loan Agreement, the Company paid $27 in financing costs to SVB, which were recorded as loan discounts. These loan discounts are included as a reduction in the balance of the term loan payable on the Company’s Condensed Consolidated Balance Sheets and will be accreted over the life of the SVB Term Loan using the effective interest method. Accretion of these loan discounts totaled $2 and $2 for the three months ended June 30, 2022 and 2021, respectively, and $5 and $5 for the six months ended June 30, 2022 and 2021, respectively, and is included in interest expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss. At June 30, 2022 and December 31, 2021, the loan discount-financing costs balance was $7 and $12, respectively. In connection with the SVB Loan Agreement, the Company is obligated to pay a final payment fee of $1.2 million upon repayment in full of the SVB Term Loan. The final payment fee is being accrued over the life of the SVB Term Loan using the effective interest method and is included as an increase in the balance of the term loan payable on the Company’s Condensed Consolidated Balance Sheets. Accrual of this final payment fee totaled $104 and $119 for the three months ended June 30, 2022 and 2021, respectively, and $220 and $237 for the six months ended June 30, 2022 and 2021, respectively, and is included in interest expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss. At June 30, 2022 and December 31, 2021, $877 and $657 was accrued for the final payment fee, respectively. Prior to the Third Amendment, the SVB Loan Agreement provided that upon SVB receiving evidence satisfactory to it that the Company had (i) received positive data for the Phase 2b/3 PRISM trial sufficient to advance Haduvio into a second Phase 3 clinical trial for prurigo nodularis and (ii) raised sufficient financing to fund such Phase 3 clinical trial and the Company’s operations, the interest rate on the SVB Term Loan would increase by 2.00% (the “Contingent Interest Rate Increase”) as described above. The Contingent Interest Rate Increase represent ed a free-standing financial instrument. Accordingly, the Company accounted for the Contingent Interest Rate Increase as a derivative under ASC 815, Derivatives and Hedging and therefore, recorded a term loan derivative liability for the Contingent Interest Rate Increase at its fair value of $ 187 on the Effective Date of the SVB Loan Agreement. The Company adjust ed this liability to fair value at each reporting date it remain ed outstanding, with such adjustments recorded as non-cash charges in other expense , net in the Company’s Condensed Consolidated Statements of Comprehensive Loss . The term loan derivative liability was presented as a current liability on the Company’s Condensed Consolidated Balance Sheet s as of December 31, 2021 . Upon recording such term loan derivative liability, the Company also recorded an offsetting term loan discount – interest, to be amortized to interest expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss through the SVB Term Loan’s maturity date using the effective interest method . Such amortization was $ 16 and $ for the three months ended June 30, 2022 and 2021 , respectively, and $ 35 and $ 37 for the six months ended June 30, 2022 and 2021 , respectively . At June 30, 2022 and December 31, 2021 , the balance of the term loan discount – interest was $ 49 and $ 84 , respectively , and is included as a reduction in the balance of the term loan payable on the Company’s Condensed Consolidated Balance Sheet s . Upon entering into the Third Amendment, the Contingent Interest Rate Increase became effective and the Company recorded an increase to the total fair value of the term loan derivative liability of $ 136 for the three months ended June 30, 2022 . The term loan derivative liability was then settled and reclassed to both current and non-current interest payable, which are presented as accrued liabilities and other non-current liabilities on the Company’s Condensed Consolidated Balance Sheet as of June 30, 2022 . Fair values of the term loan derivative liability were estimated utilizing a probability-weighted cash flow approach, including variables for the timing of the Phase 3 Event and other probability estimates. For the fair value calculations of the term loan derivative liability at June 30, 2022 and December 31, 2021, significant inputs included the Contingent Interest Rate Increase of 2.00%, a discount rate of 12.0% and the SVB Term Loan maturity date of February 1, 2024. As of June 30, 2022 and December 31, 2021, June 30, 2022 December 31, 2021 Principal outstanding under term loan $ 11,667 $ 14,000 Term loan discount-interest (49 ) (84 ) Term loan discount-unamortized deferred charges (60 ) (76 ) Term loan discount-financing costs, net of accretion (7 ) (12 ) Term loan-final payment fee 877 657 12,428 14,485 Less current portion 7,000 5,833 Term loan payable, non-current $ 5,428 $ 8,652 Interest expense on the SVB Term Loan, which is comprised of interest payments, accretion and amortization of term loan discounts and the accrual of the final payment fee, is shown below for the three and six months ended June 30, 2022 and 2021, respectively. For the three and six months ended June 30, 2022, the weighted average interest rate applicable to borrowings under the SVB Term Loan was 4.92% and 4.59%, respectively. For the three and six months ended June 30, 2021, the weighted average interest rate applicable to borrowings under the SVB Term Loan was 4.25%. Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Interest payments $ 152 $ 150 $ 300 $ 299 Accrual of the final payment fee 104 119 220 237 Accretion and amortization of term loan discounts 39 27 77 54 $ 295 $ 296 $ 597 $ 590

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2022
Stockholders Equity Note [Abstract]
Stockholders' Equity	8 . As of June 30, 2022 and December 31, 2021, the Company had reserved June 30, 2022 December 31, 2021 Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 663,089 665,720 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 4,543,352 3,400,489 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 721,717 470,631 Shares to be issued upon exercise of common stock warrants and pre-funded warrants 38,382,647 20,602,244 Shares to be issued upon sales under the LPC Purchase Agreement 30,000,000 30,000,000 74,310,805 55,139,084 At-the-Market Offering In June 2020, the Company entered into the ATM Sales Agreement with SVB Leerink LLC, under which the Company may issue and sell shares of its common stock, from time to time, having an aggregate offering price of up to $12.0 million. Sales of common stock under the ATM Sales Agreement may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended. The Company is not obligated to make any sales of its common stock under the ATM Sales Agreement. The Company began making sales pursuant to the ATM Sales Agreement in July 2020. During the three and six months ended June 30, 2021, the Company issued and sold an aggregate of 1,365,871 and 2,733,492 shares of common stock, respectively, for gross proceeds of $3.0 million and $7.4 million, respectively, before deducting estimated commissions and allocated fees of $0.3 million and $0.6 million, respectively. No sales were made during the three and six months ended June 30, 2022. As of June 30, 2022, the Company had issued and sold an aggregate of 3,583,394 shares of common stock for gross proceeds of $11.0 million, before deducting estimated commissions and allocated fees of $0.8 million. In May 2022, the Company amended the ATM Sales Agreement with SVB Leerink LLC to increase the maximum aggregate offering price of common stock that it may issue and sell from time to time under the ATM Sales Agreement by $50.0 million, from $12.0 million to up to $62.0 million. Equity Purchase Agreement On June 18, 2021, the Company entered into a common stock purchase agreement (“LPC Purchase Agreement”) with Lincoln Park Capital Fund, LLC (“Lincoln Park”). The LPC Purchase Agreement provides that, subject to the terms and conditions therein, the Company has the right, but not the obligation, to sell, at its discretion, to Lincoln Park up to $15.0 million of shares of common stock over a 24-month period commencing on July 23, 2021. In addition, under the LPC Purchase Agreement, the Company issued 170,088 shares of common stock to Lincoln Park as consideration for Lincoln Park’s commitment to purchase shares of the Company’s common stock under the LPC Purchase Agreement. The purchase price per share of the shares sold will be based on the market prices prevailing immediately preceding the time of sale as computed under the LPC Purchase Agreement. Lincoln Park has covenanted not to cause or engage in any manner whatsoever, any direct or indirect short selling or hedging of the Company’s common stock. The agreement may be terminated by the Company at any time, at its sole discretion, without any additional cost or penalty. Under the terms of the October 2021 private placements described below, the Company agreed to not issue or sell additional shares under the LPC Purchase Agreement on or prior to April 6, 2023. Private Placements On October 5, 2021, the Company issued and sold to an initial investor in a private placement priced at-the-market under Nasdaq rules, (i) 2,373,201 shares of the Company’s common stock and accompanying warrants to purchase an aggregate of 4,746,402 shares of the Company’s common stock, and (ii) pre-funded warrants to purchase up to an aggregate of 4,926,069 shares of the Company’s common stock and accompanying warrants to purchase an aggregate of 9,852,138 shares of the Company’s common stock. Each share of the Company’s common stock and accompanying common stock warrants were sold together at a combined price of $1.62, and each pre-funded warrant and accompanying common stock warrants were sold together at a combined price of $1.619, for gross proceeds of approximately $11.8 million. Each pre-funded warrant had an exercise price of $0.001 per share, became exercisable immediately upon issuance and was exercisable until exercised in full. Of the accompanying common stock warrants, warrants to purchase an aggregate of 7,299,270 shares will expire on April 5, 2025, and warrants to purchase an aggregate of 7,299,270 shares will expire on October 5, 2028. The accompanying common stock warrants have an exercise price of $1.37 per share and became exercisable immediately upon issuance. On October 18, 2021, the Company issued and sold to New Enterprise Associates 16, L.P., an existing stockholder of the Company (“NEA”) and related party, in a private placement, 1,851,852 shares of the Company’s common stock and accompanying warrants to purchase an aggregate of 3,703,704 shares of the Company’s common stock. Each share of the Company’s common stock and accompanying common stock warrants were sold together at a combined price of $ 1.62 for gross proceeds of approximately $ 3.0 million. Of the accompanying common stock warrants, warrants to purchase an aggregate of 1,851,852 shares of the Company’s common stock will expire on April 18, 2025 , and warrants to purchase an aggregate of 1,851,852 shares of the Company’s common stock will expire on October 18, 2028 . The accompanying common stock warrants have an exercise price of $ 1.37 per share and became exercisable immediately upon issuance. Total net proceeds from the two October private placements were $13.7 million, after deducting issuance costs of $1.1 million . On April 6, 2022, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) with certain purchasers, pursuant to which the Company agreed to issue and sell to the purchasers, in a private placement priced at-the-market under Nasdaq rules, (i) 4,580,526 shares of the Company’s common stock at a purchase price of $1.90 per share, and (ii) pre-funded warrants to purchase up to an aggregate of 24,379,673 shares of common stock at a purchase price of $1.899 per warrant (the “April 2022 Private Placement”). Each pre-funded warrant has an exercise price of $0.001 per share, is exercisable immediately and will be exercisable until the pre-funded warrant is exercised in full. The April 2022 Private Placement, which closed on April 11, 2022, resulted in gross proceeds to the Company of approximately $55.0 million. NEA, an existing stockholder of the Company and a related party, as well as an affiliate of NEA, participated in the offering. Warrant activity, including activity related to the pre-funded warrants, for the six months ended June 30, 2022 is shown in the table below: Number of Pre-funded Warrant Shares Number of Common Stock Warrant Shares Total Number of Warrant Shares Weighted Average Exercise Price Outstanding as of December 31, 2021 2,300,000 18,302,244 20,602,244 $ 1.22 Issued 24,379,673 — 24,379,673 $ 0.001 Exercised (2,300,000 ) (4,299,270 ) (6,599,270 ) $ 1.37 Outstanding as of June 30, 2022 24,379,673 14,002,974 38,382,647 $ 0.50 As of June 30, 2022, all of the pre-funded warrants from the October 2021 private placements had been exercised at the exercise price of $0.001 per share. The pre-funded and common stock warrants are classified as equity in accordance with ASC 815 given that the pre-funded and common stock warrants are indexed to the Company’s own shares of common stock and meet the requirements to be classified in permanent equity. In July 2022, the remaining common stock warrants from the October 2021 private placements that were set to expire on April 5, 2025 were exercised to purchase 3.0 million shares of common stock, which provided approximately $4.1 million in cash proceeds to the Company. 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, non-statutory 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. The total number of shares of common stock that may be issued under the 2019 Plan and the 2012 Stock Incentive Plan (the “2012 Plan”) was 5,206,441 as of June 30, 2022, of which 1,062,074 shares remained available for grant under the 2019 Plan. 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 2012 Plan was adopted by the Company’s board of directors and stockholders. The 2012 Plan provides for the issuance of stock-based awards to the Company’s employees, officers, directors, consultants and advisors. The Company’s board of directors administers the 2012 Plan. In April 2019, the Company’s board of directors adopted a resolution effective on May 7, 2019, that no further equity-based awards may be granted under the 2012 Plan. Options granted under the 2019 Plan and the 2012 Plan have a maximum term of ten years. Options granted to employees, officers and non-employees generally vest over four years based on varying vesting schedules that primarily include: 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 ye ars. 2,263,752 shares of common stock were granted and outstanding, net of cancellations, under the 2019 Plan. As of June 30, 2022 and December 31, 2021, respectively, options to purchase 663,089 and 665,720 shares of common stock, were granted and outstanding, net of cancellations, under the 2012 Plan. In February 2021, the compensation committee of the Company’s board of directors approved the grant of stock options to purchase 450,875 shares of common stock with performance-based vesting (“PSOs”) to employees of the Company. The PSOs granted in February 2021, vest based on the timing and successful results of the Company’s PRISM or CANAL clinical trials. A summary of the Company’s combined stock option activity for the 2019 Plan and the 2012 Plan for the six months ended June 30, 2022 is as follows: Number of Option Shares Weighted Average Exercise Price Outstanding as of December 31, 2021 2,929,472 $ 4.51 Granted 1,258,750 $ 0.68 Forfeited (41,224 ) $ 4.21 Expired (2,631 ) $ 1.43 Exercised — $ — Outstanding as of June 30, 2022 4,144,367 $ 3.35 Options exercisable as of June 30, 2022 2,005,863 $ 4.70 Options unvested as of June 30, 2022 2,138,504 $ 2.09 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 total number of shares of common stock that may be issued under the 2019 ESPP was 803,976 The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan, the 2019 Plan and the 2019 ESPP recognized in the Condensed Consolidated Statements of Comprehensive Loss: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 General and administrative expense $ 348 $ 494 $ 825 $ 1,039 Research and development expense 172 251 432 424 $ 520 $ 745 $ 1,257 $ 1,463

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	9 . As of June 30, 2022 and December 31, 2021, the Company maintained a full valuation allowance on deferred tax assets. The income tax benefit recorded during the three and six months ended June 30, 2022 and 2021 were to align the Company’s estimates for its state research and development credits in each given year.

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Net Loss per Share	10 . 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, 2022 2021 2022 2021 Net loss $ (8,052 ) $ (9,794 ) $ (15,381 ) $ (18,165 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 59,542,628 20,123,461 45,253,599 19,772,201 Basic and diluted net loss per common share outstanding $ (0.14 ) $ (0.49 ) $ (0.34 ) $ (0.92 ) Basic shares outstanding includes the weighted average effect of the Company’s pre-funded warrants from the date of issuance, the exercise of which requires little or no consideration for the delivery of shares of common stock. As of June 30, 2022, the Company had pre-funded warrants to purchase 24,379,673 share of common stock outstanding, which were issued in the April 2022 Private Placement. Such pre-funded warrants are included in the weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted in both the three and six months ended June 30 2022. The Company’s potential dilutive securities, which include stock options and warrants, 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, 2022 and 2021, respectively, 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, 2022 2021 Stock Options 4,144,367 3,202,377 Warrants 14,002,974 — 18,147,341 3,202,377

Collaborative and Licensing Agr

Collaborative and Licensing Agreements	6 Months Ended
	Jun. 30, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborative and Licensing Agreements	1 1 . 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., which subsequently merged into its parent, Endo Pharmaceuticals Inc. (“Endo”), for an exclusive worldwide sublicensable license under certain patent rights and know-how controlled by Endo to develop and commercialize products incorporating nalbuphine hydrochloride in any formulation, including an extended-release formulation such as Haduvio, in all fields and for any use. Under the license agreement, the Company paid Endo a non-creditable, non-refundable upfront license fee. The Company may also become obligated to make milestone payments to Endo of $0.3 million, which would become due upon the successful completion of the first Phase 3 clinical trial of a licensed product candidate, such as the Phase 2b/3 PRISM trial, and $0.8 million, which would become due upon the marketing approval of a licensed product in the U.S. 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. 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.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 2 . Commitments and Contingencies A significant portion of the Company’s development activities are outsourced to third parties under agreements, including with CROs 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 5 and Note 11).

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	1 3 . Subsequent Events Warrant Exercises In July 2022, the remaining common stock warrants from the October 2021 private placements that were set to expire on April 5, 2025 were exercised to purchase 3.0 million shares of common stock, which provided approximately $4.1 million in cash proceeds to the Company. See Note 8 above for further discussion of the October 2021 private placements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim Condensed Consolidated Financial Statements for the three and six months ended June 30, 2022 and 2021 included herein have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim information. Certain information and footnote disclosures 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 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 (the “Annual Report on Form 10-K”). 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, 2022 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 in Note 13.
Use of Estimates	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, the valuation of stock-based awards and the valuation allowance of deferred tax assets resulting from net operating losses. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. The inputs into the Company’s estimates also considered the economic implications of the COVID-19 pandemic on the Company’s estimates.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheet as of June 30, 2022 and the Condensed Consolidated Statements of Comprehensive Loss, the Condensed Consolidated Statements of Stockholders’ Equity and the Condensed Consolidated Statements of Cash Flows for the three and six months ended June 30, 2022 and 2021 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, 2022 and the results of its operations and its cash flows for the three and six months ended June 30, 2022 and 2021. The results for the three and six months ended June 30, 2022 and 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2022 or any other interim period or any future year or period.
Cash Equivalents	Cash Equivalents The Company classifies short-term, highly liquid investments with an original term of three months or less at the date of purchase as cash equivalents.
Marketable Securities	Marketable Securities The Company generally invests its excess cash in money market funds and investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term marketable securities or long-term marketable securities on the Condensed Consolidated Balance Sheet. Marketable securities with an original maturity date greater than 90 days and less than one year at each balance sheet date are classified as short-term. Marketable securities with a maturity date greater than one year at each balance sheet date are classified as long-term. All of the Company’s marketable securities are considered available-for-sale and are reported at fair value with unrealized gains and losses included as a component of stockholders’ equity (deficit). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on marketable securities are included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. The cost of securities sold is determined using specific identification. The Company evaluates whether declines in the fair values of its marketable securities below their amortized cost are other-than temporary on a quarterly basis. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the marketable security or whether it is more likely than not that it will be required to sell any marketable securities before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the marketable security.
Fair Value Measurement	Fair Value Measurements The Company’s financial instruments have consisted of cash and cash equivalents, available-for-sale marketable securities, other current assets, accounts payable, accrued expenses, term loans, term loan derivative liability and warrants to acquire the Company’s common stock. Fair instruments. Available-for-sale marketable securities are reported at their fair values, based upon pricing of securities with the same or similar investment characteristics as provided by third-party pricing services, as described below. The fair value of the term loan derivative liability is estimated utilizing a probability-weighted cash flow approach. The warrants to acquire the Company’s common stock are not required to be accounted for at fair value. 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, 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. Valuation Techniques - Level 2 Inputs The Company estimates the fair values of its financial instruments categorized as level 2 in the fair value hierarchy, including U.S. Treasury securities, U.S. government agency obligations, corporate bonds, commercial paper and municipal bonds, by taking into consideration valuations obtained from third-party pricing services. The pricing services use industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, benchmark yields, issuer credit spreads, benchmark securities, and other observable inputs. The Company obtains a single price for each financial instrument and does not adjust the prices obtained from the pricing service.
Property, Equipment and Leasehold Improvements	Property, Equipment and Leasehold Improvements Property, equipment and leasehold improvements (consisting of furniture, computer and office equipment and leasehold improvements) are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the respective assets (three years for computer equipment, five years for furniture and office equipment and the shorter of the term of the lease or useful life for leasehold improvements).
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets ASC 360, Property, Plant and Equipment,
Foreign Currency Transactions	Foreign Currency Transactions The Company, at times, contracts with vendors and consultants outside of the U.S., resulting in liabilities denominated in foreign currency. The transactions are recorded in U.S. dollars on the transaction dates and any currency fluctuation through the payment date is recorded as currency gains or losses in the Condensed Consolidated Statements of Comprehensive Loss.
Deferred Offering Costs	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 as a reduction of additional paid-in capital generated as a result of the financings. 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. The deferred offering costs are included in Other non-current assets on the Condensed Consolidated Balance Sheets.
Research and Development ("R&D") Expenses	Research and Development (“R&D”) Expenses All of the Company’s R&D expenses consist of expenses incurred in connection with the development of Haduvio. These expenses include certain payroll and personnel expenses, including stock-based compensation, consulting costs, contract manufacturing costs and fees paid to clinical research organizations (“CROs”) to conduct certain R&D activities on the Company’s behalf. The Company does not allocate its costs by each indication for which it is developing Haduvio, as a significant amount of the Company’s development activities broadly support all indications. In addition, several of the Company’s departments support the Company’s Haduvio drug candidate development program and the Company does not identify internal costs for each potential indication. The Company expenses both internal and external R&D expenses as they are incurred.
Accrued R&D Expenses	Accrued R&D Expenses The Company has entered into agreements with CROs, contract manufacturing organizations (“CMOs”) and other companies that provide services in connection with the Company’s R&D activities. The Company’s R&D accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events and contracted costs. The estimated costs of R&D provided, but not yet invoiced, are included in accrued expenses on the Condensed Consolidated Balance Sheets. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CROs, CMOs and other companies under these arrangements in advance of the performance of the related services are recorded as prepaid expenses or as other non-current assets, as applicable, and are recognized as expenses as the goods are delivered or the related services are performed.
Patent Costs	Patent Costs All patent-related costs in connection with filing and prosecuting patent applications are expensed to general and administrative expense as incurred, as recoverability of such expenditures is uncertain.
Warrants	Warrants The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging If warrants do not meet liability classification under ASC 480, the Company assesses the requirements under ASC 815, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815, in order to conclude equity classification, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815 or other applicable GAAP. After all relevant assessments are made, the Company concludes whether the warrants are classified as liability or equity. Liability classified warrants are required to be accounted for at fair value both on the date of issuance and on subsequent accounting period ending dates, with all changes in fair value after the issuance date recorded in the statements of comprehensive loss as a gain or loss. For equity classified warrants, no changes in fair value are recognized after the issuance date.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employees for consultancy services in accordance with ASC 718, Stock Compensation Changes in the variables can materially affect the fair value and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require analysis and judgment to develop. Expected Term—The expected term assumption represents the weighted average period that the stock-based awards are expected to be outstanding. The Company has elected to use the “simplified method” for estimating the expected term of its stock options, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the stock option. Expected Volatility—For all stock options granted to date, the volatility data was estimated based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. Expected Dividend—The Black-Scholes valuation model calls for a single expected dividend yield as an input. The Company currently has no history or expectation of paying cash dividends on its common stock. Risk-Free Interest Rate—The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the stock-based award. The fair value is recognized over the period during which an optionee is required to provide services in exchange for the stock option, known as the requisite service period (usually the vesting period) on a straight-line basis. For performance-based vesting, the fair value is recognized when the performance conditions are probable. The Company reassesses the probability of achieving the performance conditions at each reporting date. Forfeitures are accounted for as they occur.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Deferred income tax assets are reduced, as necessary, by a valuation allowance when management determines it is more likely than not that some or all of the tax benefits will not be realized. The Company applies the provisions of ASC 740, Income Taxes
Leases	Leases Under ASC 842, Leases 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.
Basic and Diluted Net Income (Loss) per Common Share	Basic and Diluted Net Income (Loss) per Common Share Basic and diluted net loss per common share outstanding is determined by dividing net loss by the weighted average common shares outstanding during the period. Basic shares outstanding includes the weighted average effect of the Company’s outstanding pre-funded warrants, the exercise of which requires little or no consideration for the delivery of shares of common stock. For all periods presented, shares issuable upon exercise of stock options and warrants to purchase shares of common stock (other than pre-funded warrants) 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 each of the periods presented.
Segments	Segments The Company has one reporting segment which is also the Company’s only operating segment. Management uses one measurement of profitability and does not segregate its business for internal reporting. All long-lived assets are maintained in the U.S.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements There have been no new pronouncements adopted during the six months ended June 30, 2022, which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the six months ended June 30, 2022, which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements.

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2022
Investments Debt And Equity Securities [Abstract]
Schedule of Fair Value And Amortized Cost Of Available-for-sale Marketable Securities	The fair value and amortized cost of available-for-sale marketable securities by major security type as of June 30, 2022 are presented in the following table (in thousands): June 30, 2022 Type of security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury securities $ 19,785 $ — $ (45 ) $ 19,740 Corporate bonds 15,485 — (90 ) 15,395 Commercial paper 19,022 — — 19,022 Total marketable securities $ 54,292 $ — $ (135 ) $ 54,157
Summary Of Remaining Contractual Maturities Of Available-for-sale Marketable Securities	As of June 30, 2022, the remaining contractual maturities of available-for-sale marketable securities were as follows (in thousands): June 30, 2022 Amortized Cost Fair Value Due to mature: Less than one year $ 53,283 $ 53,157 One year through two years 1,009 1,000 Total $ 54,292 $ 54,157

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the financial assets and financial liabilities measured at fair value on a recurring basis as of June 30, 2022 and December 31, 2021, and the basis for that measurement, by level within the fair value hierarchy: Fair Value Measurement Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total June 30, 2022 Financial assets: Cash equivalents Money market funds $ 21,699 $ — $ — $ 21,699 Cash equivalents Corporate bonds — 1,999 — 1,999 Marketable securities U.S. treasury securities 19,740 — — 19,740 Marketable securities Corporate bonds — 15,395 — 15,395 Marketable securities Commercial paper — 19,022 — 19,022 Total assets $ 41,439 $ 36,416 $ — $ 77,855 Fair Value Measurement Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total December 31, 2021 Financial assets: Cash equivalents Money market funds $ 35,835 $ — $ — $ 35,835 Total assets $ 35,835 $ — $ — $ 35,835 Financial liabilities: Term loan derivative liability $ — $ — $ 114 $ 114 Total liabilities $ — $ — $ 114 $ 114
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, 2022 December 31, 2021 Financial liabilities Balance at beginning of period $ 114 $ 196 Change in fair value of term loan derivative liability 147 (82 ) Net settlements (see Note 7) (261 ) — Balance at end of period $ — $ 114

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Schedule of Balance Sheet Information Related to Operating Leases	The following table summarizes the Company’s operating lease as presented on its Condensed Consolidated Balance Sheets: June 30, 2022 December 31, 2021 Assets: Operating lease right-of-use asset $ 82 $ 131 Liabilities: Operating lease liabilities, current portion 92 120 Operating lease liabilities, long term portion 3 24 Total operating lease liabilities $ 95 $ 144
Future Minimum Lease Payments for Non-cancellable Operating Leases	Future minimum lease payments from June 30, 2022 until the expiration of the operating leases are as follows: 2022 $ 72 2023 25 2024 2 2025 1 Total lease payments 100 Less: imputed discount rate (5 ) Carrying value of operating lease liabilities $ 95

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2022
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: June 30, 2022 December 31, 2021 Accrued R&D projects $ 2,567 $ 2,303 Accrued compensation and benefits 1,054 1,250 Accrued consulting and professional fees 450 176 Accrued other 332 79 Total accrued expenses $ 4,403 $ 3,808

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowings under SVB Term Loan	As of June 30, 2022 and December 31, 2021, June 30, 2022 December 31, 2021 Principal outstanding under term loan $ 11,667 $ 14,000 Term loan discount-interest (49 ) (84 ) Term loan discount-unamortized deferred charges (60 ) (76 ) Term loan discount-financing costs, net of accretion (7 ) (12 ) Term loan-final payment fee 877 657 12,428 14,485 Less current portion 7,000 5,833 Term loan payable, non-current $ 5,428 $ 8,652
Schedule of Components of Interest Expense of Term Loan	Interest expense on the SVB Term Loan, which is comprised of interest payments, accretion and amortization of term loan discounts and the accrual of the final payment fee, is shown below for the three and six months ended June 30, 2022 and 2021, respectively. For the three and six months ended June 30, 2022, the weighted average interest rate applicable to borrowings under the SVB Term Loan was 4.92% and 4.59%, respectively. For the three and six months ended June 30, 2021, the weighted average interest rate applicable to borrowings under the SVB Term Loan was 4.25%. Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Interest payments $ 152 $ 150 $ 300 $ 299 Accrual of the final payment fee 104 119 220 237 Accretion and amortization of term loan discounts 39 27 77 54 $ 295 $ 296 $ 597 $ 590

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Stockholders Equity Note [Abstract]
Schedule of Common Stock Reserved for Future Issuance	As of June 30, 2022 and December 31, 2021, the Company had reserved June 30, 2022 December 31, 2021 Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 663,089 665,720 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 4,543,352 3,400,489 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 721,717 470,631 Shares to be issued upon exercise of common stock warrants and pre-funded warrants 38,382,647 20,602,244 Shares to be issued upon sales under the LPC Purchase Agreement 30,000,000 30,000,000 74,310,805 55,139,084
Warrant Activity Including Activity Related To Pre-funded Warrants	Warrant activity, including activity related to the pre-funded warrants, for the six months ended June 30, 2022 is shown in the table below: Number of Pre-funded Warrant Shares Number of Common Stock Warrant Shares Total Number of Warrant Shares Weighted Average Exercise Price Outstanding as of December 31, 2021 2,300,000 18,302,244 20,602,244 $ 1.22 Issued 24,379,673 — 24,379,673 $ 0.001 Exercised (2,300,000 ) (4,299,270 ) (6,599,270 ) $ 1.37 Outstanding as of June 30, 2022 24,379,673 14,002,974 38,382,647 $ 0.50
Schedule of Share-based Compensation, Stock Options, Activity	A summary of the Company’s combined stock option activity for the 2019 Plan and the 2012 Plan for the six months ended June 30, 2022 is as follows: Number of Option Shares Weighted Average Exercise Price Outstanding as of December 31, 2021 2,929,472 $ 4.51 Granted 1,258,750 $ 0.68 Forfeited (41,224 ) $ 4.21 Expired (2,631 ) $ 1.43 Exercised — $ — Outstanding as of June 30, 2022 4,144,367 $ 3.35 Options exercisable as of June 30, 2022 2,005,863 $ 4.70 Options unvested as of June 30, 2022 2,138,504 $ 2.09
Schedule of Stock-based Compensation Expenses Recognized	The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan, the 2019 Plan and the 2019 ESPP recognized in the Condensed Consolidated Statements of Comprehensive Loss: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 General and administrative expense $ 348 $ 494 $ 825 $ 1,039 Research and development expense 172 251 432 424 $ 520 $ 745 $ 1,257 $ 1,463

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2022
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, 2022 2021 2022 2021 Net loss $ (8,052 ) $ (9,794 ) $ (15,381 ) $ (18,165 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 59,542,628 20,123,461 45,253,599 19,772,201 Basic and diluted net loss per common share outstanding $ (0.14 ) $ (0.49 ) $ (0.34 ) $ (0.92 )
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, 2022 and 2021, respectively, 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, 2022 2021 Stock Options 4,144,367 3,202,377 Warrants 14,002,974 — 18,147,341 3,202,377

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2022 USD ($) Segment
Summary Of Significant Accounting Policies [Line Items]
Dividends, common stock, cash | $	$ 0
Number of reporting segment	1
Number of operating segment	1
Computer Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Equipment and leasehold improvements, useful life	3 years
Furniture and Office Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Equipment and leasehold improvements, useful life	5 years

Marketable Securities - Schedul

Marketable Securities - Schedule of Fair Value And Amortized Cost Of Available-for-sale Marketable Securities (Detail) $ in Thousands	Jun. 30, 2022 USD ($)
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	$ 54,292
Gross Unrealized Losses	(135)
Estimated Fair Value	54,157
U.S. Treasury Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	19,785
Gross Unrealized Losses	(45)
Estimated Fair Value	19,740
Corporate Bonds [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	15,485
Gross Unrealized Losses	(90)
Estimated Fair Value	15,395
Commercial Paper [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	19,022
Estimated Fair Value	$ 19,022

Marketable Securities - Summary

Marketable Securities - Summary Of Remaining Contractual Maturities Of Available-for-sale Marketable Securities (Detail) $ in Thousands	Jun. 30, 2022 USD ($)
Investments Debt And Equity Securities [Abstract]
Amortized cost, less than one year	$ 53,283
Amortized cost, one year through two years	1,009
Amortized Cost	54,292
Fair value, less than one year	53,157
Fair Value, one year through two years	1,000
Fair Value	$ 54,157

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	3 Months Ended	6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)
Investments Debt And Equity Securities [Abstract]
Realized gains or losses on available-for-sale marketable securities	$ 0	$ 0
Marketable securities, continuous unrealized loss position, 12 months or longer	0	0
Other-than-temporary impairment losses, marketable securities	$ 0	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financial assets:
Total assets	$ 77,855	$ 35,835
Financial liabilities:
Total liabilities		114
Term Loan Derivative Liability [Member]
Financial liabilities:
Term loan derivative liability		114
Corporate Bonds [Member]
Financial assets:
Cash equivalents	1,999
Marketable securities	15,395
U.S. Treasury Securities [Member]
Financial assets:
Marketable securities	19,740
Commercial Paper [Member]
Financial assets:
Marketable securities	19,022
Level 1 [Member]
Financial assets:
Total assets	41,439	35,835
Level 1 [Member] | U.S. Treasury Securities [Member]
Financial assets:
Marketable securities	19,740
Level 2 [Member]
Financial assets:
Total assets	36,416
Level 2 [Member] | Corporate Bonds [Member]
Financial assets:
Cash equivalents	1,999
Marketable securities	15,395
Level 2 [Member] | Commercial Paper [Member]
Financial assets:
Marketable securities	19,022
Level 3 [Member]
Financial liabilities:
Total liabilities		114
Level 3 [Member] | Term Loan Derivative Liability [Member]
Financial liabilities:
Term loan derivative liability		114
Money Market Funds [Member]
Financial assets:
Cash equivalents	21,699	35,835
Money Market Funds [Member] | Level 1 [Member]
Financial assets:
Cash equivalents	$ 21,699	$ 35,835

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 114	$ 196
Net settlements (see Note 7)	(261)
Balance at end of period		114
Term Loan Derivative Liability [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Change in fair value of term loan derivative liability	$ 147	$ (82)

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 01, 2018 USD ($) ft²	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) Lease	Jun. 30, 2021 USD ($)
Operating lease, weighted average discount rate, percent		13%		13%
Number of new leases | Lease				0
Remaining terms		9 months 18 days		9 months 18 days
Operating Lease, Payments		$ 24	$ 35	$ 59	$ 69
Building [Member]
Leased spaced area | ft²	5,600
Operating lease term	60 months
Building [Member] | Minimum [Member]
Operating lease rent expense	$ 10
Building [Member] | Maximum [Member]
Operating lease rent expense	$ 12
Office Equipment [Member]
Operating lease term		36 months		36 months
Operating lease rent expense		$ 23	$ 30	$ 61	$ 61

Leases - Schedule of Balance Sh

Leases - Schedule of Balance Sheet Operating Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Operating lease right-of-use asset	$ 82	$ 131
Liabilities:
Operating lease liabilities, current portion	92	120
Operating lease liabilities, long term portion	3	24
Total operating lease liabilities	$ 95	$ 144

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Leases [Abstract]
2022	$ 72
2023	25
2024	2
2025	1
Total lease payments	100
Less: imputed discount rate	(5)
Carrying value of operating lease liabilities	$ 95	$ 144

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued R&D projects	$ 2,567	$ 2,303
Accrued compensation and benefits	1,054	1,250
Accrued consulting and professional fees	450	176
Accrued other	332	79
Total accrued expenses	$ 4,403	$ 3,808

Debt - Additional Information (

Debt - Additional Information (Detail) $ in Thousands				1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Apr. 06, 2022 USD ($)	Jul. 06, 2021 USD ($)	Aug. 13, 2020 USD ($) Installment	Oct. 31, 2021 PrivatePlacement	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Oct. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Aug. 31, 2020 USD ($)
Private Placement [Member]
Number of private placements | PrivatePlacement				2
SVB Term Loan [Member]
Debt instrument, principal amount			$ 14,000		$ 11,667			$ 11,667		$ 14,000
Interest-only payment period			24 months
Loan payment, number of consecutive equal monthly installments of principal including accrued interest | Installment			24
Debt instrument, maturity date								Feb. 01, 2024
Debt instrument, final payment fee amount			$ 1,200		1,200			$ 1,200
Debt default additional interest charge			5%
Debt finance costs		$ 68									$ 57
Amortization of deferred financing charges					20	$ 5		37	$ 11
Unamortized deferred charges					60			60		76
Financing costs paid											$ 27
Accretion loan discounts					2	2		5	5
Loan discounts-financing costs					7			7		12
Accrual of the final payment fee					104	119		220	237
Debt instrument, accrued final payment fee					877			$ 877		657
Contingent interest rate increase								2%
Amortization of term loan					16	$ 19		$ 35	$ 37
Term loan discount interest					$ 49			$ 49		$ 84
Weighted average interest rate, floating					4.92%	4.25%		4.59%	4.25%
SVB Term Loan [Member] | Term Loan Derivative Liability [Member]
Term loan derivative liability			$ 187
SVB Term Loan [Member] | Term Loan Derivative Liability [Member] | Contingent Interest Rate Increase [Member]
Derivative liability, measurement input					0.0200			0.0200
SVB Term Loan [Member] | Term Loan Derivative Liability [Member] | Discount Rate [Member]
Derivative liability, measurement input					0.120			0.120
SVB Term Loan [Member] | Minimum [Member]
Interest rate, floating			4.25%
Long term debt percentage bearing adjusted floating interest rate			6.25%
SVB Term Loan [Member] | First Amendment
Debt instruments percentage of required to deposit unrestricted and unencumbered cash collateral		100%
Equity raise requirements, description								if the Company failed to receive positive data in its Phase 2b/3 PRISM trial or to raise by June 30, 2022 sufficient net proceeds from the sale of equity securities to finance its planned second Phase 3 clinical trial of Haduvio for prurigo nodularis and its ongoing operations (each a “Milestone Condition”), the Company would be required to deposit unrestricted and unencumbered cash equal to 100% of all outstanding amounts owed to SVB in a cash collateral account with SVB, which could be used by SVB to prepay the SVB Term Loan at any time.
SVB Term Loan [Member] | First Amendment | Minimum [Member]
Proceeds from the sale of equity securities							$ 15,000
Debt instruments amount of required to maintain unrestricted and unencumbered cash		$ 20,000
SVB Term Loan [Member] | Third Amendment [Member]
Proceeds from the sale of equity securities	$ 45,000
Debt finance costs					$ 21			$ 21
SVB Term Loan [Member] | Third Amendment [Member] | Term Loan Derivative Liability [Member]
Term loan derivative liability					$ 136			$ 136
SVB Term Loan [Member] | Third Amendment [Member] | Minimum [Member]
Interest rate, floating	4.25%
Long term debt percentage bearing adjusted floating interest rate	6.25%
SVB Term Loan [Member] | Prepayment Prior to First Anniversary of Effective Date [Member]
Prepayment premium percentage on principal amount			3%
SVB Term Loan [Member] | Prepayment After First Anniversary of Effective Date and Prior To Second Anniversary of Effective Date [Member]
Prepayment premium percentage on principal amount			2%
SVB Term Loan [Member] | Prepayment After Second Anniversary of the Effective Date and Prior to February 1, 2024 [Member]
Prepayment premium percentage on principal amount			1%
SVB Term Loan [Member] | Prime Rate [Member]
Variable interest rate			1%
SVB Term Loan [Member] | Prime Rate [Member] | Third Amendment [Member]
Variable interest rate	1%
SVB Term Loan [Member] | Adjusted Prime Rate [Member]
Variable interest rate			3%
SVB Term Loan [Member] | Adjusted Prime Rate [Member] | Third Amendment [Member]
Variable interest rate	3%

Debt - Schedule of Outstanding

Debt - Schedule of Outstanding Borrowings under SVB Term Loan (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Aug. 13, 2020
Debt Instrument [Line Items]
Less current portion	$ 7,000	$ 5,833
Term loan payable, non-current	5,428	8,652
SVB Term Loan [Member]
Debt Instrument [Line Items]
Principal outstanding under term loan	11,667	14,000	$ 14,000
Term loan discount-interest	(49)	(84)
Term loan discount-unamortized deferred charges	(60)	(76)
Term loan discount-financing costs, net of accretion	(7)	(12)
Debt instrument, accrued final payment fee	877	657
Loans Payable, Noncurrent	12,428	14,485
Less current portion	7,000	5,833
Term loan payable, non-current	$ 5,428	$ 8,652

Debt - Schedule of Components o

Debt - Schedule of Components of Interest Expense of Term Loan (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Debt Instrument [Line Items]
Interest expense	$ 295	$ 296	$ 597	$ 590
SVB Term Loan [Member]
Debt Instrument [Line Items]
Interest payments	152	150	300	299
Accrual of the final payment fee	104	119	220	237
Accretion and amortization of term loan discounts	39	27	77	54
Interest expense	$ 295	$ 296	$ 597	$ 590

Stockholders' Equity - Shares R

Stockholders' Equity - Shares Reserved For Future Issuances (Detail) - shares	Jun. 30, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	74,310,805	55,139,084
Exercise of Common Stock Warrants and Pre-funded Warrants
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	38,382,647	20,602,244
LPC Purchase Agreement [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	30,000,000	30,000,000
2012 Stock Option And Grant Plan [Member] | 2012 Stock Incentive Plan [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	663,089	665,720
2019 Stock Option And Grant Plan [Member] | 2019 Stock Incentive Plan [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	4,543,352	3,400,489
2019 Stock Option And Grant Plan [Member] | 2019 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	721,717	470,631

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)

1 Months Ended

3 Months Ended

6 Months Ended

25 Months Ended

Apr. 06, 2022 USD ($) $ / shares shares

Oct. 18, 2021 USD ($) PrivatePlacement $ / shares shares

Oct. 05, 2021 USD ($) $ / shares shares

Jun. 18, 2021 shares

Jul. 31, 2022 USD ($) shares

May 31, 2022 USD ($)

Oct. 31, 2021 PrivatePlacement

Jun. 30, 2020 USD ($)

Jun. 30, 2022 $ / shares shares

Jun. 30, 2021 USD ($) shares

Jun. 30, 2022 USD ($) $ / shares shares

Jun. 30, 2021 USD ($) shares

Jun. 30, 2022 $ / shares shares

Dec. 31, 2021 $ / shares

Stockholders Equity [Line Items]

Estimated commissions and allocated fees | $

$ 34,000

$ 89,000

Proceeds from sale of common stock and warrants under private placement, net of issuance costs | $

$ 51,826,000

Common Stock, Par or Stated Value Per Share | $ / shares

$ 0.001

$ 0.001

$ 0.001

$ 0.001

Proceeds from exercises of warrants | $

$ 5,892,000

Warrant [Member]

Stockholders Equity [Line Items]

Common Stock, Par or Stated Value Per Share | $ / shares

$ 0.001

$ 0.001

$ 0.001

Private Placement [Member]

Stockholders Equity [Line Items]

Number of private placements | PrivatePlacement

2

Private Placement [Member] | Subsequent Events [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

3,000,000

Proceeds from exercises of warrants | $

$ 4,100,000

Private Placement [Member] | Investor [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

9,852,138

Private Placement [Member] | New Enterprise Associates 16, L.P [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

3,703,704

Proceeds from sale of common stock and warrants under private placement, net of issuance costs | $

$ 13,700,000

Number of private placements | PrivatePlacement

2

Proceeds from issuance of private placement net of issuance costs | $

$ 1,100,000

Private Placement [Member] | Common Stock [Member]

Stockholders Equity [Line Items]

Sale of stock during the period

4,580,526

4,580,526

Private Placement [Member] | Common Stock [Member] | Investor [Member]

Stockholders Equity [Line Items]

Sale of stock during the period

2,373,201

Warrants to purchase aggregate shares of common stock

4,746,402

Private Placement [Member] | Common Stock [Member] | New Enterprise Associates 16, L.P [Member]

Stockholders Equity [Line Items]

Sale of stock during the period

1,851,852

Private Placement [Member] | Common Stock [Member] | Securities Purchase Agreement [Member]

Stockholders Equity [Line Items]

Sale of stock during the period

4,580,526

Combined price of each shares | $ / shares

$ 1.90

Private Placement [Member] | Pre-funded Warrants [Member] | Investor [Member]

Stockholders Equity [Line Items]

Exercise price per share of warrants | $ / shares

$ 0.001

Private Placement [Member] | Pre-funded Warrants [Member] | Securities Purchase Agreement [Member]

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.899

Proceeds from sale of common stock and warrants under private placement, net of issuance costs | $

$ 55,000,000

Exercise price per share of warrants | $ / shares

$ 0.001

Private Placement [Member] | Common Stock and Accompanying Common Stock Warrants [Member] | Investor [Member]

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

1.62

Private Placement [Member] | Common Stock and Accompanying Common Stock Warrants [Member] | New Enterprise Associates 16, L.P [Member]

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.62

Proceeds from sale of common stock and warrants under private placement, net of issuance costs | $

$ 3,000,000

Private Placement [Member] | Pre-funded Warrant and Accompanying Common Stock Warrants [Member] | Investor [Member]

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.619

Proceeds from sale of common stock and warrants under private placement, net of issuance costs | $

$ 11,800,000

Private Placement [Member] | Common Stock Warrants | Investor [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

7,299,270

Exercise price per share of warrants | $ / shares

$ 1.37

Warrants expiration date

Apr. 05, 2025

Private Placement [Member] | Common Stock Warrants | New Enterprise Associates 16, L.P [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

1,851,852

Exercise price per share of warrants | $ / shares

$ 1.37

Warrants expiration date

Apr. 18, 2025

Private Placement [Member] | Warrant [Member] | Subsequent Events [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

3,000,000

Proceeds from exercises of warrants | $

$ 4,100,000

Private Placement [Member] | Warrant [Member] | Investor [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

7,299,270

Warrants expiration date

Oct. 05, 2028

Private Placement [Member] | Warrant [Member] | New Enterprise Associates 16, L.P [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

1,851,852

Warrants expiration date

Oct. 18, 2028

Maximum [Member] | Private Placement [Member] | Pre-funded Warrants [Member] | Investor [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

4,926,069

Maximum [Member] | Private Placement [Member] | Pre-funded Warrants [Member] | Securities Purchase Agreement [Member]

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

24,379,673

ATM Sales Agreement [Member]

Stockholders Equity [Line Items]

Aggregate offering price of common stock which may issue and sell under agreement | $

$ 50,000,000

$ 12,000,000

$ 62,000,000

Sale of stock during the period

0

1,365,871

0

2,733,492

3,583,394

Proceeds from issuance of common stock | $

$ 3,000,000

$ 11,000,000

$ 7,400,000

Estimated commissions and allocated fees | $

$ 300,000

$ 800,000

$ 600,000

Common Stock Purchase Agreement [Member] | Lincoln Park Capital Fund, LLC [Member]

Stockholders Equity [Line Items]

Shares agreed to be issued over period under equity line financing

24 months

Issuance of common stock to Lincoln Park Capital Fund (in shares)

170,088

Common Stock Purchase Agreement [Member] | Lincoln Park Capital Fund, LLC [Member] | Maximum [Member]

Stockholders Equity [Line Items]

Shares agreed to be issued under equity line financing

15,000,000

Stockholders' Equity - Warrant

Stockholders' Equity - Warrant Activity Including Activity Related To Pre-funded Warrants (Detail)	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Pre-funded Warrants [Member]
Number of Other than Option Shares
Outstanding, Beginning	2,300,000
Issued	24,379,673
Exercised	(2,300,000)
Outstanding, Ending	24,379,673
Common Stock Warrant [Member]
Number of Other than Option Shares
Outstanding, Beginning	18,302,244
Exercised	(4,299,270)
Outstanding, Ending	14,002,974
Warrant [Member]
Number of Other than Option Shares
Outstanding, Beginning	20,602,244
Issued	24,379,673
Exercised	(6,599,270)
Outstanding, Ending	38,382,647
Weighted Average Exercise Price
Outstanding, Beginning | $ / shares	$ 1.22
Issued | $ / shares	0.001
Exercised | $ / shares	1.37
Outstanding, Ending | $ / shares	$ 0.50

Stockholders' Equity (Stock-Bas

Stockholders' Equity (Stock-Based Awards) - Additional Information (Detail) - shares				1 Months Ended		6 Months Ended
	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020	Feb. 28, 2021	Apr. 30, 2019	Jun. 30, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance						74,310,805	55,139,084
Share based compensation options to purchase no of common stock						4,144,367	2,929,472
Share based compensation options grants in the period						1,258,750
2019 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, award description						The total number of shares of common stock that may be issued under the 2019 Plan and the 2012 Stock Incentive Plan (the “2012 Plan”) was 5,206,441 as of June 30, 2022, of which 1,062,074 shares remained available for grant under the 2019 Plan. 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.
Number of shares available for grant						1,062,074
Common stock, capital shares reserved for future issuance	1,140,232	741,871				1,578,947
Share based compensation grant period						10 years
Share based compensation vesting description						Options granted under the 2019 Plan and the 2012 Plan have a maximum term of ten years. Options granted to employees, officers and non-employees generally vest over four years based on varying vesting schedules that primarily include: 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 to purchase no of common stock						3,481,278	2,263,752
2019 Stock Incentive Plan [Member] | Employees, Officers and Non-employee Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						4 years
2019 Stock Incentive Plan [Member] | Employees, Officers and Non-employee Consultants [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%
2019 Stock Incentive Plan [Member] | Director [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						1 year
2019 Stock Incentive Plan [Member] | Director [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						2 years
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%	4%	4%
2019 Plan and 2012 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total number of common shares authorized under the plan						5,206,441
2012 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation grant period						10 years
Share based compensation vesting description						Options granted under the 2019 Plan and the 2012 Plan have a maximum term of ten years. Options granted to employees, officers and non-employees generally vest over four years based on varying vesting schedules that primarily include: 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 to purchase no of common stock						663,089	665,720
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] | Employees, Officers and Non-employee Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						4 years
2012 Stock Incentive Plan [Member] | Employees, Officers and Non-employee Consultants [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%
2012 Stock Incentive Plan [Member] | Director [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						1 year
2012 Stock Incentive Plan [Member] | Director [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period						2 years
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 number of shares outstanding						1,157,894
Performance Based Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period				450,875
2019 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, award description						The total number of shares of common stock that may be issued under the 2019 ESPP was 803,976 as of June 30, 2022, of which 721,717 shares remain available for issuance. 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. Effective January 1, 2022 and January 1, 2021, respectively, the aggregate number of shares of the Company’s common stock that may be issued under the 2019 ESPP increased, pursuant to the terms of the 2019 ESPP, by an additional 285,058 shares and 185,467 shares, in each case equal to 1% of the Company’s then-outstanding common stock
Total number of common shares authorized under the plan						803,976
Number of shares available for grant						721,717
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	285,058	185,467			526,315
Percentage of number of common stock, shares outstanding	1%	1%			1%

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options, Activity (Detail)	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Number of Option Shares
Outstanding, Beginning | shares	2,929,472
Granted | shares	1,258,750
Forfeited | shares	(41,224)
Expired | shares	(2,631)
Outstanding, Ending | shares	4,144,367
Options exercisable | shares	2,005,863
Options unvested | shares	2,138,504
Weighted Average Exercise Price
Outstanding, Beginning | $ / shares	$ 4.51
Granted | $ / shares	0.68
Forfeited | $ / shares	4.21
Expired | $ / shares	1.43
Outstanding, Ending | $ / shares	3.35
Options exercisable | $ / shares	4.70
Options unvested | $ / shares	$ 2.09

Stockholders' Equity - Stock-ba

Stockholders' Equity - Stock-based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Stock-based compensation	$ 520	$ 745	$ 1,257	$ 1,463
General and Administrative Expense [Member]
Stock-based compensation	348	494	825	1,039
Research and Development Expense [Member]
Stock-based compensation	$ 172	$ 251	$ 432	$ 424

Net Loss per Share - Computatio

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
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net loss	$ (8,052)	$ (9,794)	$ (15,381)	$ (18,165)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	59,542,628	20,123,461	45,253,599	19,772,201
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	59,542,628	20,123,461	45,253,599	19,772,201
Basic net loss per common share outstanding	$ (0.14)	$ (0.49)	$ (0.34)	$ (0.92)
Diluted net loss per common share outstanding	$ (0.14)	$ (0.49)	$ (0.34)	$ (0.92)

Net Loss per Share - Additional

Net Loss per Share - Additional Information (Details)	Jun. 30, 2022 shares
April 2022 Private Placement [Member]
Earnings Per Share Basic [Line Items]
Pre-funded warrants to purchase of common stock	24,379,673

Net Loss per Share - Calculatio

Net Loss per Share - Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive securities excluded from computation of earnings per share, amount	18,147,341	3,202,377
Stock Option [Member]
Antidilutive securities excluded from computation of earnings per share, amount	4,144,367	3,202,377
Warrant [Member]
Antidilutive securities excluded from computation of earnings per share, amount	14,002,974

Collaborative and Licensing A_2

Collaborative and Licensing Agreements - Additional Information (Detail) - Endo Pharmaceuticals Inc [Member] $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
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
Completion Of Stage One [Member]
Milestone payments to be paid	$ 0.3
Completion Of Stage Two [Member]
Milestone payments to be paid	$ 0.8

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands, shares in Millions	1 Months Ended	6 Months Ended
	Jul. 31, 2022	Jun. 30, 2022
Subsequent Event [Line Items]
Proceeds from exercises of warrants		$ 5,892
Subsequent Events [Member] | Private Placement [Member]
Subsequent Event [Line Items]
Proceeds from exercises of warrants	$ 4,100
Warrants to purchase aggregate shares of common stock	3