Trevi Therapeutics (TRVI) 10-K 16 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 16, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Registrant Name	TREVI THERAPEUTICS, INC.
Entity Central Index Key	0001563880
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 65.2
Entity Common Stock, Shares Outstanding		60,045,096
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	TRVI
Security Exchange Name	NASDAQ
Entity File Number	001-38886
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-0834299
Entity Address, Address Line One	195 Church Street
Entity Address, Address Line Two	16th 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
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Hartford, Connecticut
Documents Incorporated by Reference	Portions of the Proxy Statement for the registrant’s 2023 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 12,589	$ 36,830
Marketable securities	107,921
Prepaid expenses	795	886
Other current assets	1,311	241
Total current assets	122,616	37,957
Other non-current assets	205	334
Operating lease right-of-use asset	24	131
Property, equipment and leasehold improvements, net	170	53
Total assets	123,015	38,475
Current liabilities:
Accounts payable	2,857	2,849
Accrued expenses	3,518	3,808
Term loan	7,000	5,833
Term loan derivative liability		114
Operating lease liability	25	120
Total current liabilities	13,400	12,724
Term loan	2,151	8,652
Operating lease liability	2	24
Other non-current liabilities	3
Total liabilities	15,556	21,400
Commitments and contingencies (Note 13)
Stockholders’ equity:
Preferred stock: $0.001 par value; 5,000,000 shares authorized at December 31, 2022 and December 31, 2021; no shares issued or outstanding at December 31, 2022 and December 31, 2021.
Common stock: $0.001 par value; 200,000,000 shares authorized at December 31, 2022 and December 31, 2021; and 59,322,517 and 28,505,804 shares issued and outstanding at December 31, 2022 and December 31, 2021, respectively.	60	29
Additional paid-in capital	317,590	197,963
Accumulated other comprehensive loss	(122)
Accumulated deficit	(210,069)	(180,917)
Total stockholders’ equity	107,459	17,075
Total liabilities and stockholders’ equity	$ 123,015	$ 38,475

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 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	59,943,430	28,505,804
Common Stock, Shares, Outstanding	59,943,430	28,505,804

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating expenses:
Research and development	$ 19,834	$ 22,984
General and administrative	10,073	9,492
Total operating expenses	29,907	32,476
Loss from operations	(29,907)	(32,476)
Other income (expense):
Change in fair value of term loan derivative liability	(147)	82
Other income (expense), net	289	(375)
Interest income, net	1,740	10
Interest expense	(1,163)	(1,202)
Total other income (expense), net	719	(1,485)
Loss before income taxes	(29,188)	(33,961)
Income tax benefit	36	21
Net loss	$ (29,152)	$ (33,940)
Basic net loss per common share outstanding	$ (0.45)	$ (1.49)
Diluted net loss per common share outstanding	$ (0.45)	$ (1.49)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	64,541,911	22,841,481
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	64,541,911	22,841,481
Net loss	$ (29,152)	$ (33,940)
Net unrealized losses on available-for-sale marketable securities	(122)
Comprehensive loss	$ (29,274)	$ (33,940)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	At The Market Sales Agreement	Private Placement [Member]	Public And Private Placements	Lincoln Park Capital Fund, LLC [Member]	Common Stock [Member]	Common Stock [Member] At The Market Sales Agreement	Common Stock [Member] Private Placement [Member]	Common Stock [Member] Public And Private Placements	Common Stock [Member] Lincoln Park Capital Fund, LLC [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] At The Market Sales Agreement	Additional Paid-in Capital [Member] Private Placement [Member]	Additional Paid-in Capital [Member] Public And Private Placements	Additional Paid-in Capital [Member] Lincoln Park Capital Fund, LLC [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	2,543										2,543
Issuance of common stock from employee stock purchase plan	39										39
Issuance of common stock from employee stock purchase plan (in shares)						42,290
Issuance of common stock, net of commissions and allocated fees, less issuance costs		$ 7,095	$ 13,678				$ 3	$ 4				$ 7,092	$ 13,674
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)							2,895,518	4,225,053
Issuance of common stock to Lincoln Park Capital Fund					$ 375										$ 375
Issuance of common stock to Lincoln Park Capital Fund (in shares)										170,088
Issuance of common stock from warrant exercise	3					$ 3
Issuance of common stock from warrant exercise (in shares)						2,626,069
Net loss	(33,940)																(33,940)
Ending Balance at Dec. 31, 2021	17,075					$ 29					197,963						(180,917)
Ending Balance (in shares) at Dec. 31, 2021						28,505,804
Stock-based compensation	2,327										2,327
Issuance of common stock from exercise of stock options	$ 139										139
Issuance of common stock from exercise of stock options (in shares)	51,005					51,005
Issuance of common stock from employee stock purchase plan	$ 56										56
Issuance of common stock from employee stock purchase plan (in shares)						54,457
Issuance of common stock, net of commissions and allocated fees, less issuance costs		$ (42)		$ 105,395					$ 20			$ (42)		$ 105,375
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)									20,433,624
Issuance of common stock from warrant exercise	11,783					$ 11					11,772
Issuance of common stock from warrant exercise (in shares)						10,898,540
Unrealized losses on available-for-sale marketable securities	(122)															$ (122)
Net loss	(29,152)																(29,152)
Ending Balance at Dec. 31, 2022	$ 107,459					$ 60					$ 317,590					$ (122)	$ (210,069)
Ending Balance (in shares) at Dec. 31, 2022						59,943,430

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss	$ (29,152)	$ (33,940)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	43	50
Accretion of available-for-sale marketable securities, net	(829)
Change in fair value of term loan derivative liability	147	(82)
Accretion/accrual of term loan discounts and debt issuance costs	520	599
Other expense related to transaction with Lincoln Park Capital Fund, LLC		375
Stock-based compensation	2,327	2,543
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(601)	342
Accounts payable	9	831
Accrued expenses and other liabilities	(639)	336
Net cash used in operating activities	(28,175)	(28,946)
Investing activities:
Proceeds from maturities of available-for-sale marketable securities	19,001
Purchases of available-for-sale marketable securities	(126,215)
Purchases of property, equipment and leasehold improvements	(159)
Net cash used in investing activities	(107,373)
Financing activities:
Repayments of term loan	(5,833)
Payments of financing costs of term loan	(21)	(68)
Proceeds from sale of common stock and warrants under public offering and private placement, net of issuance costs	105,410	13,678
Proceeds from exercises of warrants	11,782	3
Proceeds from exercises of stock options	139
Proceeds from employee stock purchase plan	56	39
Proceeds from at-the-market sales, net of commissions		7,505
Payments of offering costs	(226)	(382)
Net cash provided by financing activities	111,307	20,775
Net decrease in cash and cash equivalents	(24,241)	(8,171)
Cash and cash equivalents at beginning of period	36,830	45,001
Cash and cash equivalents at end of period	12,589	36,830
Supplemental disclosure of cash flow information:
Interest paid	594	603
State research tax credits exchanged for cash		18
Supplemental disclosure of non-cash financing activities:
Offering costs included in accrued expenses	$ 15	$ 41

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Trevi Therapeutics, Inc. (“Trevi” or the “Company”) is a clinical-stage biopharmaceutical company focused on the development and commercialization of the investigational therapy Haduvio (oral nalbuphine ER) for the treatment of chronic cough in adults with idiopathic pulmonary fibrosis (“IPF”) and other chronic cough indications, and for the treatment of prurigo nodularis. 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 cough and itch. 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. The Company’s Consolidated Financial Statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has financed its operations to date primarily through private placements of its redeemable convertible preferred stock and convertible notes prior to its initial public offering (“IPO”), borrowings under its prior term loan facility, proceeds from its IPO and concurrent private placement completed in May 2019, sales of its common stock pursuant to the at-the-market Sales Agreement (the “ATM Sales Agreement”) (Note 9) with SVB Securities LLC (formerly SVB Leerink LLC) (“SVB Securities”) that the Company entered into in June 2020, the term loan facility with Silicon Valley Bank (“SVB”) that the Company entered into in August 2020 (Note 8), proceeds from the private placements completed in October 2021 and April 2022 (Note 9), proceeds from the exercise of common stock warrants that were issued in the October 2021 private placements and proceeds from the public offering completed in October 2022 (Note 9). The Company has incurred recurring losses since inception, including net losses of $ 29.2 million and $ 33.9 million for the years ended December 31, 2022 and 2021, respectively. As of December 31, 2022, the Company had cash, cash equivalents and marketable securities of $ 120.5 million compared to $ 36.8 million of cash and cash equivalents as of December 31, 2021. The Company had incurred losses and negative cash flows from operations and had an accumulated deficit of $ 210.1 million as of December 31, 2022. The Company expects to continue to incur losses for the foreseeable future. As of March 16, 2023, the date of issuance of these Consolidated Financial Statements, the Company believes that its cash, cash equivalents and marketable securities as of December 31, 2022 , will be sufficient to fund its operating expenses and capital expenditure requirements for 12 months from the date of issuance of these Consolidated Financial Statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying 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 December 31, 2022 for potential recognition or disclosure in the Consolidated Financial Statements and concluded there w ere no subsequent events that required recognition or disclosure. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. (“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 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. 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 or marketable securities on the Consolidated Balance Sheet. Marketable securities classified as current assets as these investments are intended to be available to the Company for use in funding current operations. 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. 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 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 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 value estimates of these instruments are made at a specific point in time, based on relevant market information. The carrying amounts of cash and cash equivalents, other current assets, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. 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 carrying amount of the term loan approximates its fair value due to its floating market-based interest rate. 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 , and requires certain disclosures about fair value measurements. The valuation techniques included in the guidance are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect market assumptions and are classified into the following fair value hierarchy: Level 1—Observable inputs—quoted prices in active markets for identical assets and liabilities. Level 2—Observable inputs other than the quoted prices in active markets for identical assets and liabilities—such as quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets, or other inputs that are observable or can be corroborated by observable market data. Level 3—Unobservable inputs—includes amounts derived from valuation models where one or more significant inputs are unobservable and require the company to develop relevant assumptions. 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, addresses the financial accounting and reporting for impairment or disposal of long-lived assets. The Company reviews the recorded values of long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable. There was no impairment or disposal of long-lived assets during the years ended December 31, 2022 and 2021 . 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 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 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 contract 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 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 (“ASC 480”), and then in accordance with ASC 815, Derivatives and Hedging (“ASC 815”), depending on the specific terms of the warrant. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the issuer to settle the warrants or the underlying shares by paying cash or other assets, or must or may require settlement by issuing variable number of shares. If the 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 (“ASC 718”). ASC 718 requires the recognition of compensation expense, using a fair-value based method, for costs related to all stock-based awards including stock options. The Company’s determination of the fair value of stock-based awards on the date of grant utilizes the Black-Scholes valuation model for stock options with time-based and performance-based vesting and is impacted by the price of its common stock as well as changes in assumptions regarding a number of subjective variables. These variables include the expected term that stock options will remain outstanding, expected common stock price volatility over the term of the stock options, risk-free interest rates and expected dividends. 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 it is probable the performance conditions will be achieved. 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 Taxe s (“ASC 740”), which prescribes a comprehensive model for how a company should recognize, measure, present and disclose in its financial statements uncertain tax positions that the company has taken or expects to take on a tax return. These Consolidated Financial Statements reflect expected future tax consequences of such positions presuming the taxing authorities possess full knowledge of the position and all relevant facts. There are no material uncertainties regarding the tax positions that the Company has taken through December 31, 2022 and December 31, 2021 . The Company does not have any interest or penalties accrued related to tax positions as it does not have any unrecognized tax benefits. Leases Under ASC 842, Leases (“ASC 842”), the Company determines if an arrangement is a lease at its inception. If an operating lease has a term greater than one year, the lease is recognized in the balance sheet as a right-of-use asset and an operating lease liability at lease commencement. The Company elected the short-term lease practical expedient, therefore, if an operating lease has a term less than one year, the Company will not recognize the lease on its balance sheet. The operating right-of-use asset represents the Company’s right of use to an underlying asset for the term of the lease and the operating liability represents the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and operating lease liabilities are determined and recognized on the commencement date of the lease based on the present value of lease payments over the term of the lease. As the Company’s leases do not provide an implicit rate within the lease, the Company uses its incremental borrowing rate, based on information available at the commencement date of the lease to determine the present value of the lease payments. Basic and Diluted Net 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 year ended December 31, 2022 , which materially impacted the Company’s Consolidated Financial Statements. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the year ended December 31, 2022 , which could be expected to materially impact the Company’s Consolidated Financial Statements.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 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 December 31, 2022 are presented in the following table (in thousands): December 31, 2022 Type of Security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury securities $ 9,914 $ — $ ( 62 ) $ 9,852 Asset backed securities 1,912 2 — 1,914 U.S. government agency securities 2,905 2 ( 4 ) 2,903 Corporate bonds 62,573 83 ( 143 ) 62,513 Commercial paper 30,739 — — 30,739 Total marketable securities $ 108,043 $ 87 $ ( 209 ) $ 107,921 The net amortized cost and fair value of available-for-sale marketable securities at December 31, 2022 are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company intends to sell a security prior to maturity. December 31, 2022 Amortized Cost Fair Value Due to mature: Less than one year $ 69,527 $ 69,367 One year through two years 38,516 38,554 Total $ 108,043 $ 107,921 During the year ended December 31, 2022 , there have been no realized gains or losses on available-for-sale marketable securities. During the year ended December 31, 2022 , no marketable securities had been in a continuous unrealized loss position for more than 12 months and the Company did no t recognize any other-than-temporary impairment losses on marketable securities.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 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 December 31, 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 December 31, 2022 Financial assets: Cash equivalents Money market funds $ 11,589 $ — $ — $ 11,589 Marketable securities U.S. treasury securities 9,852 — — 9,852 Marketable securities Asset backed securities — 1,914 — 1,914 Marketable securities U.S. government agency securities — 2,903 — 2,903 Marketable securities Corporate bonds — 62,513 — 62,513 Marketable securities Commercial paper — 30,739 — 30,739 Total assets $ 21,441 $ 98,069 $ — $ 119,510 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): December 31, 2022 2021 Financial liabilities Balance at beginning of period $ 114 $ 196 Change in fair value of term loan derivative liability 147 ( 82 ) Net settlements ( 261 ) — Balance at end of period $ — $ 114

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	5. Leases The Company entered into a lease for office space in New Haven, CT, effective March 1, 2013, and entered into a First Amendment to such lease on December 5, 2017 and a Second Amendment (the “Second Amendment”) to such lease on November 21, 2022 (collectively, the “Office Space Lease”). The leased space approximates 5,600 square feet and, prior to the Second Amendment, the Office Space Lease had a term of 60 months expiring on February 28, 2023 . Under the First Amendment, the Company was required to make monthly payments ranging from approximately $ 10 to $ 12 through February 1, 2023 and provided for two designated months of free rent. As a result of the Company entering into the Second Amendment, the leased space will increase to 12,500 square feet effective in March 2023 and the term for the Office Space Lease was extended for an additional 60 months from its prior termination date, until February 28, 2028 . The Second Amendment to the Office Space Lease requires monthly payments ranging from approximately $ 23 to $ 32 effective in March 2023, when the lease space is available for use, and through February 2028 and includes a tenant improvement allowance of approximately $ 670 . The Second Amendment space was not available as of December 31, 2022 and therefore the Company has no t recorded a related right-of-use asset or operating lease liability. In December 2022, the Company entered into a 24 month lease for the financing of the furniture that will be installed as part of the Company's new office space. The furniture lease requires monthly payments of approximately $ 11 once the furniture is delivered, which is estimated to occur in March 2023. The furniture had not been received as of December 31, 2022 and therefore the Company has no t recorded a related right-of-use asset or lease liability. 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 First Amendment to 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, except for the Second Amendment to the Office Space Lease, during the years ended December 31, 2022 and 2021. The First Amendment to the Office Space Lease was an operating lease and the remaining term as of December 31, 2022 was less than one year . The Company has no financing leases. The following table summarizes the Company’s operating leases as presented on its Consolidated Balance Sheets: December 31, 2022 December 31, 2021 Assets: Operating lease right-of-use asset $ 24 $ 131 Liabilities: Operating lease liabilities, current portion 25 120 Operating lease liabilities, long term portion 2 24 Total operating lease liabilities $ 27 $ 144 Future minimum lease payments from December 31, 2022 until the expiration of the operating lease are as follows: 2023 $ 25 2024 2 2025 1 2026 — Total lease payments 28 Less: imputed discount rate ( 1 ) Carrying value of operating lease liabilities $ 27 Lease expense under operating leases, including leases of office equipment, was $ 123 and $ 120 for the years ended December 31, 2022 and 2021, respectively. Lease payments made were $ 130 and $ 139 in the years ended December 31, 2022 and 2021 , respectively, with such amounts reflected in the Consolidated Statements of Cash Flows in operating activities.

Property, Equipment and Leaseho

Property, Equipment and Leasehold Improvements, Net	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property, Equipment and Leasehold Improvements, Net	6. Property, Equipment and Leasehold Improvements, Net Property, equipment and leasehold improvements, net consist of the following: December 31, 2022 2021 Computer, website development and office equipment $ 175 $ 45 Furniture and fixtures 37 60 Leasehold improvements 130 130 Construction in progress 53 — 395 235 Less: Accumulated depreciation ( 225 ) ( 182 ) Total property, equipment and leasehold improvements, net $ 170 $ 53 Depreciation was $ 43 and $ 50 for the years ended December 31, 2022 and 2021 , respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued Expenses	7. Accrued Expenses Accrued expenses consist of the following: December 31, 2022 2021 Accrued compensation and benefits $ 1,508 $ 1,250 Accrued R&D projects 1,130 2,303 Accrued other 498 79 Accrued consulting and professional fees 382 176 Total accrued expenses $ 3,518 $ 3,808

Debt

Debt	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt	8. 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 was required to make monthly interest payments and 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, 20 24 . 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 SVB Loan Agreement. Under the Loan Amendment, 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. In addition, the Loan Amendment provided that if the Company failed to maintain at least $ 20.0 million in unrestricted and unencumbered cash in its accounts with SVB at any time prior to the satisfaction of all the Milestone Conditions (the "Minimum Required Cash"), the Company would be required to cash collateralize all outstanding amounts owed to SVB under the SVB Loan 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 9). On April 6, 2022, the Company and SVB entered into a Third Amendment (the “Third Amendment”) to the SVB Loan Agreement. The Third Amendment principally modified the conditions under which the Company would be required to cash collateralize all outstanding amounts owed to SVB under the SVB Loan Agreement. Under the terms of the Third Amendment, if the Company raised $ 45.0 million in net proceeds from the sale of equity securities (the “2022 Equity Event”), the Company’s obligations to achieve the Milestone Conditions and maintain the Minimum Required Cash would terminate and the sole remaining trigger for cash collateralization would be if the Company did not receive positive final data by December 31, 2022 from either its Phase 2b/3 PRISM trial of Haduvio for prurigo nodularis or its Phase 2 CANAL trial of Haduvio for the treatment of chronic cough in adults with IPF. In addition, the Third Amendment modified the interest rate on the principal amount outstanding under the Loan Agreement. As a result of the Third Amendment, amounts outstanding under the Loan Agreement accrue interest at a floating per annum rate equal to (i) prior to the occurrence of the 2022 Equity Event, the greater of (A) the prime rate plus 1.00 % and (B) 4.25 %, and (ii) upon and after the occurrence of the 2022 Equity Event, the greater of (A) the prime rate plus 3.00 % and (B) 6.25 %. The closing of the April 2022 Private Placement, as discussed in Note 8 below, constituted the 2022 Equity Event and thereby terminated the Company’s obligations to achieve the Milestone Conditions and maintain the Minimum Required Cash. On August 3, 2022, SVB confirmed that the reported data from the Phase 2b/3 PRISM trial satisfied the requirement for positive final data and that the cash collateralization requirements of the SVB Loan Agreement were no longer in effect. 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 $ 68 and $ 40 for the years ended December 31, 2022 and 2021, respectively, and is included in interest expense in the Company’s Consolidated Statements of Comprehensive Loss. The unamortized deferred charges at December 31, 2022 and 2021 totaled $ 29 and $ 76 , respectively, and are included as a direct reduction of the carrying value of the term loan payable on the Company’s 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 Consolidated Balance Sheet and will be accreted over the life of the SVB Term Loan using the effective interest method. Accretion of these loan discounts totaled $ 9 and $ 11 for the years ended December 31, 2022 and 2021, respectively and is included in interest expense in the Company’s Consolidated Statements of Comprehensive Loss. At December 31, 2022 and 2021 , the loan discount-financing costs unamortized balance was $ 3 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 Consolidated Balance Sheets. Accrual of this final payment fee totaled $ 383 and $ 474 for the years ended December 31, 2022 and 2021, respectively, and is included in interest expense in the Company’s Consolidated Statements of Comprehensive Loss. At December 31, 2022 and 2021 , $ 1,040 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 represented 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 adjusted this liability to fair value at each reporting date it remained outstanding, with such adjustments recorded as non-cash charges in other income (expense), net in the Company’s Consolidated Statements of Comprehensive Loss. The term loan derivative liability was presented as a current liability on the Company’s Consolidated Balance Sheets 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 Consolidated Statements of Comprehensive Loss through the SVB Term Loan’s maturity date using the effective interest method. Such amortization was $ 60 and $ 74 for the years ended December 31, 2022 and 2021, respectively. At December 31, 2022 and 2021 , the balance of the term loan discount – interest was $ 24 and $ 84 , respectively, and is included as a reduction in the balance of the term loan payable on the Company’s Consolidated Balance Sheets. 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 Consolidated Balance Sheet as of December 31, 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 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 December 31, 2022 and December 31, 2021 , the Company had outstanding borrowings of $ 8.2 million and $ 14.0 million, respectively, under the SVB Term Loan and the term loan payable balance as presented in the Company’s Consolidated Balance Sheets as of December 31, 2022 and 2021 was comprised as shown below. December 31, 2022 2021 Principal outstanding under term loan $ 8,167 $ 14,000 Term loan discount-interest ( 24 ) ( 84 ) Term loan discount-unamortized deferred charges ( 29 ) ( 76 ) Term loan discount-financing costs, net of accretion ( 3 ) ( 12 ) Term loan-final payment fee 1,040 657 9,151 14,485 Less current portion 7,000 5,833 Term loan payable, non-current $ 2,151 $ 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 years ended December 31, 2022 and 2021. As of December 31, 2022 and 2021 , the interest rate applicable to borrowings under the SVB Term Loan was 5.36 % and 4.25 %, respectively. Year Ended December 31, 2022 2021 Interest payments $ 643 $ 603 Accrual of the final payment fee 383 474 Accretion and amortization of term loan discounts 137 125 $ 1,163 $ 1,202

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Stockholders' Equity	9. Stockholders’ Equity Preferred Stock As of December 31, 2022 and 2021 , the Company’s restated certificate of incorporation authorized the Company to issue 5,000,000 shares of preferred stock, with a par value of $ 0.001 per share. Common Stock As of December 31, 2022 and 2021 , the Company’s restated certificate of incorporation authorized the Company to issue 200,000,000 shares of common stock, with a par value of $ 0.001 per share. As of December 31, 2022 and 2021, the Company had reserved shares of common stock for future issuance as shown in the table below: December 31, December 31, Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 602,231 665,720 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 4,553,202 3,400,489 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 701,232 470,631 Shares to be issued upon exercise of common stock warrants and pre-funded warrants 48,330,707 20,602,244 Shares to be issued upon sales under the LPC Purchase Agreement 30,000,000 30,000,000 84,187,372 55,139,084 At-the-Market Offering In June 2020, the Company entered into the ATM Sales Agreement with SVB Securities, 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, and as of December 31, 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 Securities 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 2021 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. Public Offering On September 27, 2022, the Company issued and sold 14,252,670 shares of the Company's common stock and, in lieu of common stock to certain investors, pre-funded warrants to purchase 14,247,330 shares of common stock in a public offering (the "September 2022 Offering"), at a public offering price of $ 1.93 per share of common stock and $ 1.929 per pre-funded warrant pursuant to an underwriting agreement (the "Underwriting Agreement") with SVB Securities, Stifel, Nicolaus & Company, Incorporated and Oppenheimer & Co. Inc., as representatives of the several underwriters (the “Underwriters”). 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. Under the terms of the Underwriting Agreement, the Company agreed not to issue and sell additional shares until after November 21, 2022 except in certain circumstances, including the issuance and sale of additional shares pursuant to the Underwriting Agreement. Under the terms of the Underwriting Agreement, the Company granted the Underwriters an option (the "Option"), exercisable for 30 days, to purchase up to an additional 4,275,000 shares of common stock (the "Additional Shares"), at the public offering price of $ 1.93 per share. The Underwriters partially exercised the Option to purchase 1,600,428 Additional Shares, which shares were issued and sold on October 25, 2022. The September 2022 Offering, including the initial closing on September 27, 2022 and the Option closing on October 25, 2022, resulted in aggregate gross proceeds to the Company of approximately $ 58.1 million. Warrants Warrant activity, including activity related to pre-funded warrants, for the year ended December 31, 2022 is shown in the table below: Number of Number of Total Number of Weighted Weighted Outstanding as of December 31, 2021 2,300,000 18,302,244 20,602,244 $ 1.22 4.5 Issued 38,627,003 — 38,627,003 $ 0.001 Exercised ( 2,300,000 ) ( 8,598,540 ) ( 10,898,540 ) $ 1.37 Outstanding as of December 31, 2022 38,627,003 9,703,704 48,330,707 $ 0.28 5.1 As of March 31, 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. Stock-Based Awards The 2012 Stock Incentive Plan (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. 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 Plan was 5,155,433 and 4,066,209 as of December 31, 2022 and 2021 , respectively, of which 705,150 and 1,136,737 shares remained available for grant under the 2019 Plan, respectively. 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) 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. Effective January 1, 2022 and January 1, 2021 , respectively, the number of shares reserved for issuance under the 2019 Plan increased, pursuant to the terms of the 2019 Plan, by an additional 1,140,232 shares and 741,871 shares, equal to 4 % of the Company’s then-outstanding common stock. 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. Options granted to directors generally vest over one to two years . As of December 31, 2022 and 2021 , respectively, options to purchase 3,848,052 and 2,263,752 shares of common stock were granted and outstanding, net of cancelations, under the 2019 Plan. As of December 31, 2022 and 2021 , respectively, options to purchase 602,231 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 year ended December 31, 2022 is as follows: Number of Weighted Weighted Aggregate (in years) (in thousands) Outstanding as of December 31, 2021 2,929,472 $ 4.51 7.6 $ — Granted 1,669,250 $ 1.11 Forfeited ( 53,513 ) $ 3.59 Expired ( 43,921 ) $ 5.26 Exercised ( 51,005 ) $ 2.73 Outstanding as of December 31, 2022 4,450,283 $ 3.26 7.6 $ 1,672 Options exercisable as of December 31, 2022 2,196,428 $ 4.71 6.3 $ 65 Options unvested as of December 31, 2022 2,253,855 $ 1.84 8.9 $ 1,607 The weighted average grant-date fair value per share of stock options granted was $ 0.93 and $ 2.28 for the years ended December 31, 2022 and 2021, respectively. The aggregate fair value of stock options that vested during the years ended December 31, 2022 and 2021 was $ 2.9 million and $ 2.4 million, respectively. The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the year ended December 31, 2022 was $ 33 . No stock options were exercised during the year ended December 31, 2021. The assumptions that the Company used to determine the fair value of the stock options granted were as follows, presented on a weighted average basis: Year Ended December 31, 2022 2021 Risk-free interest rate 2.4 % 0.8 % Expected volatility 103.3 % 94.0 % Expected dividend yield — — Expected life of options (in years) 6.9 6.5 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 as of December 31, 2022 , of which 701,232 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, equal to 1 % of the Company’s then-outstanding common stock. 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 Consolidated Statements of Comprehensive Loss: Year Ended December 31, 2022 2021 General and administrative expense $ 1,512 $ 1,800 Research and development expense 815 743 $ 2,327 $ 2,543 As of December 31, 2022 , total unrecognized compensation cost related to the unvested share-based awards was $ 2.9 million, which is expected to be recognized over a weighted average period of 2.4 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes During the years ended December 31, 2022 and 2021 , the Company recorded an income tax benefit related to state research and development tax credits of $ 36 and $ 21 , respectively. The components of income tax benefit for the years ended December 31, 2022 and 2021, are as follows: Year Ended December 31, 2022 2021 Current: Federal $ — $ — State ( 36 ) ( 21 ) ( 36 ) ( 21 ) Deferred: Federal — — State — — — — Income tax benefit $ ( 36 ) $ ( 21 ) The following table provides a reconciliation between income tax benefit and the expected tax benefit at the statutory rate for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 2021 Federal statutory income tax rate 21.0 % 21.0 % State income tax benefit—net of federal tax 5.8 6.0 Change in valuation allowance ( 28.7 ) ( 29.1 ) Refundable tax credit 0.1 0.1 R&D tax credits 2.5 2.1 Permanent adjustments ( 0.6 ) — Effective income tax rate 0.1 % 0.1 % Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2022 2021 Net operating loss carryforwards $ 48,030 $ 45,693 Federal and state tax credits 5,569 4,801 Capitalized R&D 4,825 — Other 2,868 2,237 Deferred tax assets 61,292 52,731 Other ( 220 ) ( 35 ) Deferred tax liabilities ( 220 ) ( 35 ) Valuation allowance ( 61,072 ) ( 52,696 ) Net deferred tax asset $ — $ — For the years ended December 31, 2022 and 2021 , the Company generated federal and state net operating losses (“NOLs”) of approximately $ 8.7 million and $ 32.1 million, respectively. At December 31, 2022 and 2021, the federal and state net operating loss balances were approximately $ 178.4 million and $ 169.7 million, respectively. The operating losses generated prior to 2018 will expire in years 2031 through 2037 , unless previously utilized. The operating losses generated in 2018 or later can be carried forward indefinitely, however will only offset 80 % of taxable income in a carryforward year. The Company also generated federal R&D tax credits for the years ended December 31, 2022 and 2021 of approximately $ 756 and $ 702 , respectively. At December 31, 2022 and 2021 , the federal R&D tax credit carryforwards were approximately $ 5.4 million and $ 4.6 million, respectively. These credits will expire in years 2032 through 2042 , unless previously utilized. The Company completed a detailed Section 382 analysis, and due to multiple historical ownership changes, the Company's NOLs as of December 31, 2022 , in the amount of $ 178.4 million and R&D tax credits in the amount of $ 5.4 million are subject to limitation. If a further ownership change occurs, the Company's ability to use its tax attributes might be further limited. The Company also generated state research tax credits for the years ended December 31, 2022 and 2021 of approximately $ 118 and $ 149 , respectively. The Company applied to exchange a portion of these credits for cash under a state-run program. These amounts, $ 36 and $ 21 for the years ended December 31, 2022 and 2021, respectively, were recognized as current income tax benefits in the Company’s Consolidated Statements of Comprehensive Loss. At each of December 31, 2022 and 2021 , the Company’s Consolidated Balance Sheets reflect income tax receivables of $ 36 and $ 21 respectively, related to these credits. Because of the net operating loss and research credit carryforwards, tax years 2012 through 2021 remain open to U.S. federal and state tax examinations. Beginning in 2022, the Tax Cuts and Jobs Act of 2017 ("TCJA") eliminated the option to deduct research and development expenditures in the current year and requires taxpayers to amortize U.S. expenses over five years and non-U.S. expenses over fifteen years pursuant to Internal Revenue Code Section 174. In the future, Congress may consider legislation that would defer the amortization requirement to later years, possibly with retroactive effect. In the meantime, we expect to continue to capitalize research and development expenses under the current tax law. The impact of Section 174 on the Company's deferred tax assets depends on the amount of research and development expenditures incurred by the Company and whether the IRS issues guidance on the provision, which differs from the Company's current interpretation, among other things. For the year ended December 31, 2022, this provision resulted in a deferred tax asset of $ 4,825 . Income taxes are provided using the asset/liability method, in which deferred taxes are recognized for the tax consequences of temporary differences between the financial statement carrying amounts and tax bases of existing assets and liabilities. The Company reviews deferred tax assets for recoverability on a regular basis. In assessing the need for a valuation allowance, the Company considers both positive and negative evidence related to the likelihood of realization of the deferred tax assets. The weight given to the positive and negative evidence is commensurate with the extent to which the evidence may be objectively verified. Accounting guidance states that a cumulative loss in recent years is a significant piece of negative evidence that is difficult to overcome in determining that a valuation allowance is not needed against deferred tax assets. As such, it is generally difficult for positive evidence regarding projected future taxable income exclusive of reversing taxable temporary differences to outweigh objective negative evidence of recent financial reporting losses. The Company determined that operating losses it incurred since its inception on March 17, 2011, represented negative evidence sufficient to conclude a valuation allowance was necessary. As such, the Company has recorded a valuation allowance of $ 61.1 million and $ 52.7 million at December 31, 2022 and 2021 , respectively, as a reserve against its net deferred tax assets. These balances reflect increases in the valuation allowance of $ 8.4 million and $ 9.9 million in 2022 and 2021, respectively, both representing an increase in net deferred tax assets. The Company applies the provisions of ASC 740, which prescribes a comprehensive model for how a company should recognize, measure, present, and disclose in its financial statements uncertain tax positions that the Company has taken or expects to take on a tax return. The financial statements reflect expected future tax consequences of such positions presuming the taxing authorities possess full knowledge of the position and all relevant facts. As a result of the implementation of ASC 740, the Company recognized no adjustment for unrecognized income tax benefits. The Company has not, as of yet, conducted a study of R&D tax credit carryforwards. Such a study could result in an adjustment to the Company’s R&D tax credit carryforwards; however, until a study is completed and any potential adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company’s R&D tax credits and, if an adjustment is required in the future, this adjustment would be offset by a corresponding adjustment to the valuation allowance. For the years ended December 31, 2022 and 2021 , the Company had no unrecognized tax benefits or related interest and penalties accrued. In the event the Company determines that accrual of interest or penalties are necessary in the future, the amount will be presented as a component of interest expense.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss per Share	11. Net Loss per Share The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Year Ended December 31, 2022 2021 Net loss $ ( 29,152 ) $ ( 33,940 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 64,541,911 22,841,481 Basic and diluted net loss per common share outstanding $ ( 0.45 ) $ ( 1.49 ) 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 December 31, 2022 , the Company had pre-funded warrants to purchase 38,627,003 shares of common stock outstanding, which were issued in the April 2022 Private Placement and the September 2022 Offering, which warrants are included in the weighted average common shares used in calculating the net loss per share attributable to common stockholders, basic and diluted, for the year ended December 31, 2022. The Company’s potential dilutive securities, which include stock options and warrants that are not pre-funded, 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 December 31, 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 December 31, 2022 2021 Stock Options 4,450,283 2,929,472 Warrants 9,703,704 20,602,244 14,153,987 23,531,716

Collaborative and Licensing Agr

Collaborative and Licensing Agreements	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative and Licensing Agreements	12. Collaborative and Licensing Agreements The Company enters into collaborative and licensing agreements with pharmaceutical companies to in-license, develop, manufacture and/or market products that fit within its business strategy. Endo Pharmaceuticals Inc. In May 2011, the Company entered into an agreement with Penwest Pharmaceuticals Co., 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, and $ 0.8 million, which would become due upon the marketing approval of a licensed product in the U.S. and to pay 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	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies A significant portion of the Company’s development activities are outsourced to third parties under agreements, including with 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 12).

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Retirement Plan	14. Retirement Plan In March 2013, the Company adopted and became a participating employer of a multiple employer defined contribution retirement plan that complies with Section 401(k) of the Code. All eligible employees of the Company are able to immediately participate in the plan (with an entry date of the first day of any month), with no minimum service requirement. The 401(k) plan provides that the Company make non-discretionary matching contributions of 50 % of the first 6 % of elective contributions. Participants are immediately vested in their contributions, as well as any earnings thereon. Vesting in the employer match contribution portion of their accounts, as well as any earnings thereon, is based on years of credited service, vesting over a four-year period, with 25 % vesting per completed year. The Company’s expense under the 401(k) plan, representing its employer matching contributions and additional contributions in accordance with regulatory compliance requirements, totaled $ 90 and $ 96 for the years ended December 31, 2022 and 2021 , respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying 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 December 31, 2022 for potential recognition or disclosure in the Consolidated Financial Statements and concluded there w ere no subsequent events that required recognition or disclosure.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. (“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 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.
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 or marketable securities on the Consolidated Balance Sheet. Marketable securities classified as current assets as these investments are intended to be available to the Company for use in funding current operations. 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. 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 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 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	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 value estimates of these instruments are made at a specific point in time, based on relevant market information. The carrying amounts of cash and cash equivalents, other current assets, accounts payable and accrued expenses are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. 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 carrying amount of the term loan approximates its fair value due to its floating market-based interest rate. 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 , and requires certain disclosures about fair value measurements. The valuation techniques included in the guidance are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect market assumptions and are classified into the following fair value hierarchy: Level 1—Observable inputs—quoted prices in active markets for identical assets and liabilities. Level 2—Observable inputs other than the quoted prices in active markets for identical assets and liabilities—such as quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets, or other inputs that are observable or can be corroborated by observable market data. Level 3—Unobservable inputs—includes amounts derived from valuation models where one or more significant inputs are unobservable and require the company to develop relevant assumptions. 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, addresses the financial accounting and reporting for impairment or disposal of long-lived assets. The Company reviews the recorded values of long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable. There was no impairment or disposal of long-lived assets during the years ended December 31, 2022 and 2021 .
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 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 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 contract 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 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 (“ASC 480”), and then in accordance with ASC 815, Derivatives and Hedging (“ASC 815”), depending on the specific terms of the warrant. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the issuer to settle the warrants or the underlying shares by paying cash or other assets, or must or may require settlement by issuing variable number of shares. If the 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 (“ASC 718”). ASC 718 requires the recognition of compensation expense, using a fair-value based method, for costs related to all stock-based awards including stock options. The Company’s determination of the fair value of stock-based awards on the date of grant utilizes the Black-Scholes valuation model for stock options with time-based and performance-based vesting and is impacted by the price of its common stock as well as changes in assumptions regarding a number of subjective variables. These variables include the expected term that stock options will remain outstanding, expected common stock price volatility over the term of the stock options, risk-free interest rates and expected dividends. 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 it is probable the performance conditions will be achieved. 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 Taxe s (“ASC 740”), which prescribes a comprehensive model for how a company should recognize, measure, present and disclose in its financial statements uncertain tax positions that the company has taken or expects to take on a tax return. These Consolidated Financial Statements reflect expected future tax consequences of such positions presuming the taxing authorities possess full knowledge of the position and all relevant facts. There are no material uncertainties regarding the tax positions that the Company has taken through December 31, 2022 and December 31, 2021 . The Company does not have any interest or penalties accrued related to tax positions as it does not have any unrecognized tax benefits.
Leases	Leases Under ASC 842, Leases (“ASC 842”), the Company determines if an arrangement is a lease at its inception. If an operating lease has a term greater than one year, the lease is recognized in the balance sheet as a right-of-use asset and an operating lease liability at lease commencement. The Company elected the short-term lease practical expedient, therefore, if an operating lease has a term less than one year, the Company will not recognize the lease on its balance sheet. The operating right-of-use asset represents the Company’s right of use to an underlying asset for the term of the lease and the operating liability represents the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and operating lease liabilities are determined and recognized on the commencement date of the lease based on the present value of lease payments over the term of the lease. As the Company’s leases do not provide an implicit rate within the lease, the Company uses its incremental borrowing rate, based on information available at the commencement date of the lease to determine the present value of the lease payments.
Basic and Diluted Net Loss per Common Share	Basic and Diluted Net 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 year ended December 31, 2022 , which materially impacted the Company’s Consolidated Financial Statements. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the year ended December 31, 2022 , which could be expected to materially impact the Company’s Consolidated Financial Statements.

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2022 are presented in the following table (in thousands): December 31, 2022 Type of Security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury securities $ 9,914 $ — $ ( 62 ) $ 9,852 Asset backed securities 1,912 2 — 1,914 U.S. government agency securities 2,905 2 ( 4 ) 2,903 Corporate bonds 62,573 83 ( 143 ) 62,513 Commercial paper 30,739 — — 30,739 Total marketable securities $ 108,043 $ 87 $ ( 209 ) $ 107,921
Summary Of Contractual Maturities Of Available-for-sale Marketable Securities	The net amortized cost and fair value of available-for-sale marketable securities at December 31, 2022 are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company intends to sell a security prior to maturity. December 31, 2022 Amortized Cost Fair Value Due to mature: Less than one year $ 69,527 $ 69,367 One year through two years 38,516 38,554 Total $ 108,043 $ 107,921

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 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 December 31, 2022 Financial assets: Cash equivalents Money market funds $ 11,589 $ — $ — $ 11,589 Marketable securities U.S. treasury securities 9,852 — — 9,852 Marketable securities Asset backed securities — 1,914 — 1,914 Marketable securities U.S. government agency securities — 2,903 — 2,903 Marketable securities Corporate bonds — 62,513 — 62,513 Marketable securities Commercial paper — 30,739 — 30,739 Total assets $ 21,441 $ 98,069 $ — $ 119,510 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): December 31, 2022 2021 Financial liabilities Balance at beginning of period $ 114 $ 196 Change in fair value of term loan derivative liability 147 ( 82 ) Net settlements ( 261 ) — Balance at end of period $ — $ 114

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Schedule of Balance Sheet Information Related to Operating Leases	The following table summarizes the Company’s operating leases as presented on its Consolidated Balance Sheets: December 31, 2022 December 31, 2021 Assets: Operating lease right-of-use asset $ 24 $ 131 Liabilities: Operating lease liabilities, current portion 25 120 Operating lease liabilities, long term portion 2 24 Total operating lease liabilities $ 27 $ 144
Future Minimum Lease Payments for Non-cancellable Operating Leases	Future minimum lease payments from December 31, 2022 until the expiration of the operating lease are as follows: 2023 $ 25 2024 2 2025 1 2026 — Total lease payments 28 Less: imputed discount rate ( 1 ) Carrying value of operating lease liabilities $ 27

Property, Equipment and Lease_2

Property, Equipment and Leasehold Improvements, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Summary of Property, Equipment and Leasehold Improvements, Net	Property, equipment and leasehold improvements, net consist of the following: December 31, 2022 2021 Computer, website development and office equipment $ 175 $ 45 Furniture and fixtures 37 60 Leasehold improvements 130 130 Construction in progress 53 — 395 235 Less: Accumulated depreciation ( 225 ) ( 182 ) Total property, equipment and leasehold improvements, net $ 170 $ 53

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following: December 31, 2022 2021 Accrued compensation and benefits $ 1,508 $ 1,250 Accrued R&D projects 1,130 2,303 Accrued other 498 79 Accrued consulting and professional fees 382 176 Total accrued expenses $ 3,518 $ 3,808

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowings under SVB Term Loan	Company had outstanding borrowings of $ 8.2 million and $ 14.0 million, respectively, under the SVB Term Loan and the term loan payable balance as presented in the Company’s Consolidated Balance Sheets as of December 31, 2022 and 2021 was comprised as shown below. December 31, 2022 2021 Principal outstanding under term loan $ 8,167 $ 14,000 Term loan discount-interest ( 24 ) ( 84 ) Term loan discount-unamortized deferred charges ( 29 ) ( 76 ) Term loan discount-financing costs, net of accretion ( 3 ) ( 12 ) Term loan-final payment fee 1,040 657 9,151 14,485 Less current portion 7,000 5,833 Term loan payable, non-current $ 2,151 $ 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 years ended December 31, 2022 and 2021. As of December 31, 2022 and 2021 , the interest rate applicable to borrowings under the SVB Term Loan was 5.36 % and 4.25 %, respectively. Year Ended December 31, 2022 2021 Interest payments $ 643 $ 603 Accrual of the final payment fee 383 474 Accretion and amortization of term loan discounts 137 125 $ 1,163 $ 1,202

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Reserved for Future Issuance	As of December 31, 2022 and 2021, the Company had reserved shares of common stock for future issuance as shown in the table below: December 31, December 31, Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 602,231 665,720 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 4,553,202 3,400,489 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 701,232 470,631 Shares to be issued upon exercise of common stock warrants and pre-funded warrants 48,330,707 20,602,244 Shares to be issued upon sales under the LPC Purchase Agreement 30,000,000 30,000,000 84,187,372 55,139,084
Warrant Activity Including Activity Related To Pre-funded Warrants	Warrant activity, including activity related to pre-funded warrants, for the year ended December 31, 2022 is shown in the table below: Number of Number of Total Number of Weighted Weighted Outstanding as of December 31, 2021 2,300,000 18,302,244 20,602,244 $ 1.22 4.5 Issued 38,627,003 — 38,627,003 $ 0.001 Exercised ( 2,300,000 ) ( 8,598,540 ) ( 10,898,540 ) $ 1.37 Outstanding as of December 31, 2022 38,627,003 9,703,704 48,330,707 $ 0.28 5.1
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 year ended December 31, 2022 is as follows: Number of Weighted Weighted Aggregate (in years) (in thousands) Outstanding as of December 31, 2021 2,929,472 $ 4.51 7.6 $ — Granted 1,669,250 $ 1.11 Forfeited ( 53,513 ) $ 3.59 Expired ( 43,921 ) $ 5.26 Exercised ( 51,005 ) $ 2.73 Outstanding as of December 31, 2022 4,450,283 $ 3.26 7.6 $ 1,672 Options exercisable as of December 31, 2022 2,196,428 $ 4.71 6.3 $ 65 Options unvested as of December 31, 2022 2,253,855 $ 1.84 8.9 $ 1,607
Assumptions on Fair Value of the Stock Options Granted	The assumptions that the Company used to determine the fair value of the stock options granted were as follows, presented on a weighted average basis: Year Ended December 31, 2022 2021 Risk-free interest rate 2.4 % 0.8 % Expected volatility 103.3 % 94.0 % Expected dividend yield — — Expected life of options (in years) 6.9 6.5
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 Consolidated Statements of Comprehensive Loss: Year Ended December 31, 2022 2021 General and administrative expense $ 1,512 $ 1,800 Research and development expense 815 743 $ 2,327 $ 2,543

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Components of Income Tax Benefit	The components of income tax benefit for the years ended December 31, 2022 and 2021, are as follows: Year Ended December 31, 2022 2021 Current: Federal $ — $ — State ( 36 ) ( 21 ) ( 36 ) ( 21 ) Deferred: Federal — — State — — — — Income tax benefit $ ( 36 ) $ ( 21 )
Reconciliation Between Income Tax Benefit and Expected Tax Benefit at Statutory Rate	The following table provides a reconciliation between income tax benefit and the expected tax benefit at the statutory rate for the years ended December 31, 2022 and 2021: Year Ended December 31, 2022 2021 Federal statutory income tax rate 21.0 % 21.0 % State income tax benefit—net of federal tax 5.8 6.0 Change in valuation allowance ( 28.7 ) ( 29.1 ) Refundable tax credit 0.1 0.1 R&D tax credits 2.5 2.1 Permanent adjustments ( 0.6 ) — Effective income tax rate 0.1 % 0.1 %
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2022 2021 Net operating loss carryforwards $ 48,030 $ 45,693 Federal and state tax credits 5,569 4,801 Capitalized R&D 4,825 — Other 2,868 2,237 Deferred tax assets 61,292 52,731 Other ( 220 ) ( 35 ) Deferred tax liabilities ( 220 ) ( 35 ) Valuation allowance ( 61,072 ) ( 52,696 ) Net deferred tax asset $ — $ —

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 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: Year Ended December 31, 2022 2021 Net loss $ ( 29,152 ) $ ( 33,940 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 64,541,911 22,841,481 Basic and diluted net loss per common share outstanding $ ( 0.45 ) $ ( 1.49 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potential common shares, presented based on shares outstanding as of December 31, 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 December 31, 2022 2021 Stock Options 4,450,283 2,929,472 Warrants 9,703,704 20,602,244 14,153,987 23,531,716

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net income loss	$ (29,152)	$ (33,940)
Retained earnings accumulated deficit	(210,069)	(180,917)
Cash, cash equivalents and marketable securities	120,500
Cash and cash equivalents, at carrying value	$ 12,589	$ 36,830

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets	$ 0	$ 0
Disposal of long-lived assets	0	$ 0
Dividends, common stock, cash	$ 0
Number of reporting segment | Segment	1
Number of operating segment | 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	Dec. 31, 2022 USD ($)
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	$ 108,043
Gross Unrealized Gains	87
Gross Unrealized Losses	(209)
Estimated Fair Value	107,921
U.S. Treasury Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	9,914
Gross Unrealized Losses	(62)
Estimated Fair Value	9,852
Asset Backed Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	1,912
Gross Unrealized Gains	2
Estimated Fair Value	1,914
U.S. Government Agency Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	2,905
Gross Unrealized Gains	2
Gross Unrealized Losses	(4)
Estimated Fair Value	2,903
Corporate Bonds [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	62,573
Gross Unrealized Gains	83
Gross Unrealized Losses	(143)
Estimated Fair Value	62,513
Commercial Paper [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	30,739
Estimated Fair Value	$ 30,739

Marketable Securities - Summary

Marketable Securities - Summary Of Contractual Maturities Of Available-for-sale Marketable Securities (Detail) $ in Thousands	Dec. 31, 2022 USD ($)
Investments, Debt and Equity Securities [Abstract]
Amortized cost, less than one year	$ 69,527
Amortized cost, one year through two years	38,516
Amortized Cost	108,043
Fair value, less than one year	69,367
Fair Value, one year through two years	38,554
Fair Value	$ 107,921

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($)
Investments, Debt and Equity Securities [Abstract]
Realized gains or losses on available-for-sale marketable securities	$ 0
Marketable securities, continuous unrealized loss position, 12 months or longer	0
Other-than-temporary impairment losses, marketable securities	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financial assets:
Total assets	$ 119,510	$ 35,835
Financial liabilities:
Total liabilities		114
U.S. Treasury Securities [Member]
Financial assets:
Marketable securities	9,852
Asset Backed Securities [Member]
Financial assets:
Marketable securities	1,914
U.S. Government Agency Securities [Member]
Financial assets:
Marketable securities	2,903
Corporate Bonds [Member]
Financial assets:
Marketable securities	62,513
Commercial Paper [Member]
Financial assets:
Marketable securities	30,739
Level 1 [Member]
Financial assets:
Total assets	21,441	35,835
Level 1 [Member] | U.S. Treasury Securities [Member]
Financial assets:
Marketable securities	9,852
Level 2 [Member]
Financial assets:
Total assets	98,069
Level 2 [Member] | Asset Backed Securities [Member]
Financial assets:
Marketable securities	1,914
Level 2 [Member] | U.S. Government Agency Securities [Member]
Financial assets:
Marketable securities	2,903
Level 2 [Member] | Corporate Bonds [Member]
Financial assets:
Marketable securities	62,513
Level 2 [Member] | Commercial Paper [Member]
Financial assets:
Marketable securities	30,739
Level 3 [Member]
Financial liabilities:
Total liabilities		114
Term Loan Derivative Liability [Member]
Financial liabilities:
Term loan derivative liability		114
Term Loan Derivative Liability [Member] | Level 3 [Member]
Financial liabilities:
Term loan derivative liability		114
Money Market Funds [Member]
Financial assets:
Cash equivalents	11,589	35,835
Money Market Funds [Member] | Level 1 [Member]
Financial assets:
Cash equivalents	$ 11,589	$ 35,835

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Fair Value, Financial Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 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	(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			1 Months Ended	12 Months Ended
	Nov. 21, 2022 USD ($) ft²	Dec. 05, 2017 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) Lease	Dec. 31, 2021 USD ($) Lease	Jun. 30, 2022
Operating lease, weighted average discount rate, percent			13%	13%
Number of new leases | Lease				0	0
Remaining terms			1 year	1 year
Operating Lease, Payments				$ 130	$ 139
Operating lease right-of-use asset			$ 24	24	131
Operating lease liability			$ 27	$ 27	144
Building [Member]
Leased spaced area | ft²	12,500	5,600
Lease expiration date	Feb. 28, 2028	Feb. 28, 2023
Operating lease term	60 months	60 months
Tenant improvement allowance	$ 670
Term of required monthly payments	2028-02
Operating lease right-of-use asset	$ 0
Operating lease liability	0
Building [Member] | Minimum [Member]
Operating lease rent expense	23	$ 10
Building [Member] | Maximum [Member]
Operating lease rent expense	$ 32	$ 12
Furniture [Member]
Operating lease term			24 months	24 months
Operating lease rent expense			$ 11
Operating lease right-of-use asset			0	$ 0
Operating lease liability			$ 0	0
Office Equipment [Member]
Operating lease term						36 months
Operating lease rent expense				$ 123	$ 120

Leases - Schedule of Balance Sh

Leases - Schedule of Balance Sheet Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Operating lease right-of-use asset	$ 24	$ 131
Liabilities:
Operating lease liabilities, current portion	25	120
Operating lease liabilities, long term portion	2	24
Total operating lease liabilities	$ 27	$ 144

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
2023	$ 25
2024	2
2025	1
Total lease payments	28
Less: imputed discount rate	(1)
Carrying value of operating lease liabilities	$ 27	$ 144

Property, Equipment and Lease_3

Property, Equipment and Leasehold Improvements, Net - Summary of Property, Equipment and Leasehold Improvements, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property, equipment and leasehold improvements	$ 395	$ 235
Less: Accumulated depreciation	(225)	(182)
Total property, equipment and leasehold improvements, net	170	53
Computer, Website Development And Office Equipment [Member]
Property Plant And Equipment [Line Items]
Property, equipment and leasehold improvements	175	45
Furniture And Fixtures [Member]
Property Plant And Equipment [Line Items]
Property, equipment and leasehold improvements	37	60
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, equipment and leasehold improvements	130	$ 130
Construction in Progress [Member]
Property Plant And Equipment [Line Items]
Property, equipment and leasehold improvements	$ 53

Property, Equipment and Lease_4

Property, Equipment and Leasehold Improvements, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation	$ 43	$ 50

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued compensation and benefits	$ 1,508	$ 1,250
Accrued R&D projects	1,130	2,303
Accrued other	498	79
Accrued consulting and professional fees	382	176
Total accrued expenses	$ 3,518	$ 3,808

Debt - Additional Information (

Debt - Additional Information (Detail) $ in Thousands				1 Months Ended	5 Months Ended	12 Months Ended
	Apr. 06, 2022 USD ($)	Jul. 06, 2021 USD ($)	Aug. 13, 2020 USD ($) Installment	Oct. 31, 2021 PrivatePlacement	Oct. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Aug. 31, 2020 USD ($)
Private Placement [Member]
Number of private placements | PrivatePlacement				2
SVB Term Loan [Member]
Debt instrument, principal amount			$ 14,000			$ 8,167	$ 14,000
Interest rate, floating						5.36%	4.25%
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
Debt default additional interest charge			5%
Debt finance costs		$ 68							$ 57
Unamortized deferred charges						29	$ 76
Financing costs paid									$ 27
Accretion loan discounts						9	11
Loan discounts-financing costs						3	12
Accrual of the final payment fee						383	474
Debt instrument, accrued final payment fee						$ 1,040	657
Contingent interest rate increase						2%
Amortization of term loan						$ 60	74
Term loan discount interest						$ 24	84
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
SVB Term Loan [Member] | Term Loan Derivative Liability [Member] | Discount Rate [Member]
Derivative liability, measurement input						0.120
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] | Third Amendment [Member]
Variable interest rate	3%
Proceeds from the sale of equity securities	$ 45,000
Debt finance costs						$ 21
Amortization of deferred financing charges						68	40
Unamortized deferred charges						$ 29	$ 76
SVB Term Loan [Member] | Third Amendment [Member] | Term Loan Derivative Liability [Member]
Term loan derivative liability								$ 136
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] | Minimum [Member] | First Amendment
Proceeds from the sale of equity securities					$ 15,000
Debt Instruments Amount Required To Maintain Unrestricted And Unencumbered Cash		$ 20,000
SVB Term Loan [Member] | Minimum [Member] | Third Amendment [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%
Prime Rate [Member] | SVB Term Loan [Member]
Variable interest rate			1%
Prime Rate [Member] | SVB Term Loan [Member] | Third Amendment [Member]
Variable interest rate	1%
Adjusted Prime Rate [Member] | SVB Term Loan [Member]
Variable interest rate			3%

Debt - Schedule of Outstanding

Debt - Schedule of Outstanding Borrowings under SVB Term Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Aug. 13, 2020
Debt Instrument [Line Items]
Less current portion	$ 7,000	$ 5,833
Term loan payable, non-current	2,151	8,652
SVB Term Loan [Member]
Debt Instrument [Line Items]
Principal outstanding under term loan	8,167	14,000	$ 14,000
Term loan discount-interest	(24)	(84)
Term loan discount-unamortized deferred charges	(29)	(76)
Term loan discount-financing costs, net of accretion	(3)	(12)
Debt instrument, accrued final payment fee	1,040	657
Loans Payable, Noncurrent	9,151	14,485
Less current portion	7,000
Term loan payable, non-current	$ 2,151	$ 8,652

Debt- Schedule of Components of

Debt- Schedule of Components of Interest Expense of Term Loan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Interest expense	$ 1,163	$ 1,202
SVB Term Loan [Member]
Debt Instrument [Line Items]
Interest payments	643	603
Accrual of the final payment fee	383	474
Accretion and amortization of term loan discounts	137	125
Interest expense	$ 1,163	$ 1,202

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)						1 Months Ended			12 Months Ended
	Sep. 27, 2022 USD ($) $ / shares shares	Apr. 06, 2022 USD ($) $ / shares shares	Oct. 18, 2021 USD ($) PrivatePlacement $ / shares shares	Oct. 05, 2021 USD ($) $ / shares shares	Jun. 18, 2021 shares	May 31, 2022 USD ($)	Oct. 31, 2021 PrivatePlacement	Jun. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2022 $ / shares
Stockholders Equity [Line Items]
Preferred Stock, Shares Authorized									5,000,000	5,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares									$ 0.001	$ 0.001
Common stock, shares authorized									200,000,000	200,000,000
Common stock, par or stated value per share | $ / shares									$ 0.001	$ 0.001
Estimated commissions and allocated fees | $									$ 226,000	$ 382,000
Proceeds from sale of common stock and warrants under public offering and private placement, net of issuance costs | $									105,410,000	$ 13,678,000
Private Placement [Member]
Stockholders Equity [Line Items]
Number of private placements | PrivatePlacement							2
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 public offering and 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
September 2022 Offering [Member] | Underwriting Agreement [Member]
Stockholders Equity [Line Items]
Proceeds from sale of common stock and warrants under public offering and private placement, net of issuance costs | $	$ 58,100,000
Warrants expiration date	Sep. 27, 2022
Common Stock [Member] | Private Placement [Member]
Stockholders Equity [Line Items]
Sale of stock during the period										4,225,053
Common Stock [Member] | Private Placement [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
Common Stock [Member] | Private Placement [Member] | New Enterprise Associates 16, L.P [Member]
Stockholders Equity [Line Items]
Sale of stock during the period			1,851,852
Common Stock [Member] | Private Placement [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
Common Stock [Member] | September 2022 Offering [Member] | Underwriting Agreement [Member]
Stockholders Equity [Line Items]
Sale of stock during the period	14,252,670
Combined price of each shares | $ / shares	$ 1.93
Exercise price per share of warrants | $ / shares	$ 0.001
Pre-funded Warrants [Member] | Private Placement [Member] | Investor [Member]
Stockholders Equity [Line Items]
Exercise price per share of warrants | $ / shares				$ 0.001
Pre-funded Warrants [Member] | Private Placement [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 public offering and private placement, net of issuance costs | $		$ 55,000,000
Exercise price per share of warrants | $ / shares		$ 0.001
Pre-funded Warrants [Member] | September 2022 Offering [Member] | Underwriting Agreement [Member]
Stockholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	14,247,330
Combined price of each shares | $ / shares	$ 1.929
Options to purchase additional shares	1,600,428
Common Stock and Accompanying Common Stock Warrants [Member] | Private Placement [Member] | Investor [Member]
Stockholders Equity [Line Items]
Combined price of each shares | $ / shares				1.62
Common Stock and Accompanying Common Stock Warrants [Member] | Private Placement [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 public offering and private placement, net of issuance costs | $			$ 3,000,000
Pre-funded Warrant and Accompanying Common Stock Warrants [Member] | Private Placement [Member] | Investor [Member]
Stockholders Equity [Line Items]
Combined price of each shares | $ / shares				$ 1.619
Proceeds from sale of common stock and warrants under public offering and private placement, net of issuance costs | $				$ 11,800,000
Common Stock Warrants | Private Placement [Member] | 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
Common Stock Warrants | Private Placement [Member] | 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
Warrants [Member]
Stockholders Equity [Line Items]
Common stock, par or stated value per share | $ / shares											$ 0.001
Warrants [Member] | Private Placement [Member] | Investor [Member]
Stockholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock				7,299,270
Warrants expiration date				Oct. 05, 2028
Warrants [Member] | Private Placement [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] | Pre-funded Warrants [Member] | Private Placement [Member] | Investor [Member]
Stockholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock				4,926,069
Maximum [Member] | Pre-funded Warrants [Member] | Private Placement [Member] | Securities Purchase Agreement [Member]
Stockholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock		24,379,673
Maximum [Member] | Pre-funded Warrants [Member] | September 2022 Offering [Member] | Underwriting Agreement [Member]
Stockholders Equity [Line Items]
Warrants to purchase aggregate shares of common stock	4,275,000
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									3,583,394
Proceeds from issuance of common stock | $									$ 11,000,000
Estimated commissions and allocated fees | $									$ 800,000
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 - Shares R

Stockholders' Equity - Shares Reserved For Future Issuances (Detail) - shares	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	84,187,372	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	48,330,707	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	602,231	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	4,553,202	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	701,232	470,631

Stockholders' Equity - Warrant

Stockholders' Equity - Warrant Activity Including Activity Related To Pre-funded Warrants (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Pre-funded Warrants [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, Beginning	2,300,000
Issued	38,627,003
Exercised	(2,300,000)
Outstanding, Ending	38,627,003	2,300,000
Common Stock Warrant [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, Beginning	18,302,244
Exercised	(8,598,540)
Outstanding, Ending	9,703,704	18,302,244
Warrants [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding, Beginning	20,602,244
Issued	38,627,003
Exercised	(10,898,540)
Outstanding, Ending	48,330,707	20,602,244
Weighted Average Exercise Price
Outstanding, Beginning	$ 1.22
Issued	0.001
Exercised	1.37
Outstanding, Ending	$ 0.28	$ 1.22
Weighted Average Contractual Term, Outstanding	5 years 1 month 6 days	4 years 6 months

Stockholders' Equity (Stock-Bas

Stockholders' Equity (Stock-Based Awards) - Additional Information (Detail) - USD ($)				1 Months Ended		12 Months Ended
	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020	Feb. 28, 2021	Apr. 30, 2019	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance						84,187,372	55,139,084
Share based compensation options grants in the period						1,669,250
Share based compensation options to purchase no of common stock						4,450,283	2,929,472
Weighted average fair value of options granted						$ 0.93	$ 2.28
Fair value of stock options vested						$ 2,900,000	$ 2,400,000
Fair value of stock options exercised						33,000	$ 0
Share-based awards, cost not yet recognized, amount						$ 2,900,000
Share-based award, cost not yet recognized, period for recognition						2 years 4 months 24 days
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 Plan was 5,155,433 and 4,066,209 as of December 31, 2022 and 2021, respectively, of which 705,150 and 1,136,737 shares remained available for grant under the 2019 Plan, respectively. 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) 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						705,150	1,136,737
Common stock, capital shares reserved for future issuance	1,140,232	741,871				1,578,947
Share based compensation options grants in the period						3,848,052	2,263,752
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						3,848,052	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						5,155,433	4,066,209
2012 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period						602,231	665,720
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						602,231	665,720
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
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
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 December 31, 2022, of which 701,232 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, 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						701,232
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%
Performance Based Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period				450,875

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options, Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Number of Option Shares
Outstanding, Beginning	2,929,472
Granted	1,669,250
Forfeited	(53,513)
Expired	(43,921)
Exercised	(51,005)
Outstanding, Ending	4,450,283	2,929,472
Options exercisable	2,196,428
Options unvested	2,253,855
Weighted Average Exercise Price
Outstanding, Beginning	$ 4.51
Granted	1.11
Forfeited	3.59
Expired	5.26
Exercised	2.73
Outstanding, Ending	3.26	$ 4.51
Options exercisable	4.71
Options unvested	$ 1.84
Weighted Average Contractual Term, Outstanding	7 years 7 months 6 days	7 years 7 months 6 days
Weighted Average Contractual Term, Options exercisable	6 years 3 months 18 days
Weighted Average Contractual Term, Options unvested	8 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding	$ 1,672
Aggregate Intrinsic Value, Options exercisable	65
Aggregate Intrinsic Value, Options unvested	$ 1,607

Stockholders' Equity - Assumpti

Stockholders' Equity - Assumptions on Fair Value of the Stock Options Granted (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	2.40%	0.80%
Expected volatility	103.30%	94%
Expected life of options (in years)	6 years 10 months 24 days	6 years 6 months

Stockholders' Equity - Stock-ba

Stockholders' Equity - Stock-based Compensation Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 2,327	$ 2,543
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,512	1,800
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 815	$ 743

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Current:
State	$ (36)	$ (21)
Current Federal, State and Local, Tax Expense (Benefit), Total	(36)	(21)
Deferred:
Income tax benefit	$ (36)	$ (21)

Income Taxes - Reconciliation B

Income Taxes - Reconciliation Between Income Tax Benefit and Expected Tax Benefit at Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21%	21%
State income tax benefit—net of federal tax	5.80%	6%
Change in valuation allowance	(28.70%)	(29.10%)
Refundable tax credit	0.10%	0.10%
R&D tax credits	2.50%	2.10%
Permanent adjustments	(0.60%)
Effective income tax rate	0.10%	0.10%

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 48,030	$ 45,693
Federal and state tax credits	5,569	4,801
Capitalized R&D	4,825
Other	2,868	2,237
Deferred tax assets	61,292	52,731
Other	(220)	(35)
Deferred tax liabilities	(220)	(35)
Valuation allowance	$ (61,072)	$ (52,696)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Income tax benefit	$ 36,000	$ 21,000
Operating loss carryforwards	178,400,000
R&D tax credits	5,400,000
Current state and local tax benefits	36,000	21,000
Current research tax credit receivable	36,000	21,000
Deferred tax assets, capitalize research and development expenses	4,825,000
Deferred tax assets, valuation allowance	61,072,000	52,696,000
Increase (decrease) in deferred tax assets valuation allowance	8,400,000	9,900,000
Unrecognized tax benefits or related interest and penalties accrued	0	0
Federal and State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	8,700,000	32,100,000
Operating loss carryforwards	$ 178,400,000	169,700,000
Percentage of taxable income offset by operating loss carryforwards	80%
Federal and State [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Operating loss carryforwards expiration year	2031
Income tax examination year under examination	2012
Federal and State [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Operating loss carryforwards expiration year	2037
Income tax examination year under examination	2021
Federal [Member]
Income Taxes [Line Items]
R&D tax credits	$ 756,000	702,000
Federal [Member] | R&D [Member]
Income Taxes [Line Items]
Tax credits carryforwards	$ 5,400,000	4,600,000
Federal [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax credit carryforwards expiration year	2032
Federal [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax credit carryforwards expiration year	2042
State [Member]
Income Taxes [Line Items]
R&D tax credits	$ 118,000	$ 149,000

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	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net loss	$ (29,152)	$ (33,940)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	64,541,911	22,841,481
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	64,541,911	22,841,481
Basic net loss per common share outstanding	$ (0.45)	$ (1.49)
Diluted net loss per common share outstanding	$ (0.45)	$ (1.49)

Net Loss per Share - Additional

Net Loss per Share - Additional Information (Detail)	Dec. 31, 2022 shares
April 2022 Private Placement [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Pre-funded warrants to purchase of common stock	38,627,003

Net Loss per Share - Calculatio

Net Loss per Share - Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	14,153,987	23,531,716
Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,450,283	2,929,472
Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	9,703,704	20,602,244

Collaborative and Licensing A_2

Collaborative and Licensing Agreements - Additional Information (Detail) - Endo Pharmaceuticals Inc [Member] $ in Millions	12 Months Ended
	Dec. 31, 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

Retirement Plan - Additional In

Retirement Plan - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 31, 2013	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Matching contributions, percent	50%
Defined contribution plan elective contributions percent of match	6%
Defined contribution plan, vesting period	4 years
Defined contribution plan, employers matching contribution, annual vesting percentage	25%
Defined contribution plan employers matching contribution compliance with regulatory capital requirements		$ 90	$ 96