Trevi Therapeutics (TRVI) 10-Q 9 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Nov. 09, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Registrant Name	TREVI THERAPEUTICS, INC.
Entity Central Index Key	0001563880
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Trading Symbol	TRVI
Entity Common Stock, Shares Outstanding		63,857,622
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	true
Entity File Number	001-38886
Entity Tax Identification Number	45-0834299
Entity Address, Address Line One	195 Church Street
Entity Address, Address Line Two	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
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 25,965	$ 12,589
Marketable securities	62,903	107,921
Prepaid expenses	4,039	795
Other current assets	1,046	1,311
Total current assets	93,953	122,616
Operating lease right-of-use assets	1,190	24
Other non-current assets	297	205
Property, equipment and leasehold improvements, net	238	170
Finance lease right-of-use assets	218
Total assets	95,896	123,015
Current liabilities:
Accounts payable	1,256	2,857
Accrued expenses	3,625	3,518
Operating lease liabilities	171	25
Finance lease liabilities	121
Term loan		7,000
Total current liabilities	5,173	13,400
Operating lease liabilities	1,051	2
Finance lease liabilities	62
Term loan		2,151
Other non-current liabilities		3
Total liabilities	6,286	15,556
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock: $0.001 par value; 5,000,000 shares authorized at September 30, 2023 and December 31, 2022; no shares issued or outstanding at September 30, 2023 and December 31, 2022.
Common stock: $0.001 par value; 200,000,000 shares authorized at September 30, 2023 and December 31, 2022; and 63,855,330 and 59,943,430 shares issued and outstanding at September 30, 2023 and December 31, 2022, respectively.	64	60
Additional paid-in capital	321,076	317,590
Accumulated other comprehensive loss	(217)	(122)
Accumulated deficit	(231,313)	(210,069)
Total stockholders’ equity	89,610	107,459
Total liabilities and stockholders’ equity	$ 95,896	$ 123,015

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
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	63,855,330	59,943,430
Common Stock, Shares, Outstanding	63,855,330	59,943,430

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating expenses:
Research and development	$ 6,323	$ 5,769	$ 17,165	$ 15,517
General and administrative	2,722	2,636	7,825	7,733
Total operating expenses	9,045	8,405	24,990	23,250
Loss from operations	(9,045)	(8,405)	(24,990)	(23,250)
Other income (expense):
Interest income, net	1,183	424	3,611	623
Other income, net	154		472
Interest expense	(3)	(292)	(387)	(889)
Change in fair value of term loan derivative liability				(147)
Total other income (expense), net	1,334	132	3,696	(413)
Loss before income taxes	(7,711)	(8,273)	(21,294)	(23,663)
Income tax benefit	13	7	50	16
Net loss	$ (7,698)	$ (8,266)	$ (21,244)	$ (23,647)
Basic net loss per common share outstanding	$ (0.08)	$ (0.12)	$ (0.21)	$ (0.44)
Diluted net loss per common share outstanding	$ (0.08)	$ (0.12)	$ (0.21)	$ (0.44)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	99,325,540	68,898,810	98,880,882	53,221,949
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	99,325,540	68,898,810	98,880,882	53,221,949
Net loss	$ (7,698)	$ (8,266)	$ (21,244)	$ (23,647)
Other comprehensive loss:
Net unrealized gains (losses) on available-for-sale marketable securities	31	(128)	(95)	(263)
Comprehensive loss	$ (7,667)	$ (8,394)	$ (21,339)	$ (23,910)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	At The Market Sales Agreement	Public Offering	Common Stock [Member]	Common Stock [Member] At The Market Sales Agreement	Common Stock [Member] Public Offering	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] At The Market Sales Agreement	Additional Paid-in Capital [Member] Public Offering	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2021	$ 17,075			$ 29			$ 197,963				$ (180,917)
Beginning Balance (in shares) at Dec. 31, 2021				28,505,804
Stock-based compensation	1,826						1,826
Issuance of common stock from exercise of stock options	139						139
Issuance of common stock from exercise of stock options (in shares)				51,005
Issuance of common stock, net of commissions and allocated fees, less issuance costs		$ (42)	$ 103,010			$ 19		$ (42)	$ 102,991
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)						18,833,196
Issuance of common stock from Employee Stock Purchase Plan	23						23
Issuance of common stock from Employee Stock Purchase Plan (in share)				33,972
Issuance of common stock from warrant exercise	11,782			$ 10			11,772
Issuance of common stock from warrant exercise (in shares)				10,898,540
Unrealized gains (losses) on available-for-sale marketable securities	(263)									$ (263)
Net loss	(23,647)										(23,647)
Ending Balance at Sep. 30, 2022	109,903			$ 58			314,672			(263)	(204,564)
Ending Balance (in shares) at Sep. 30, 2022				58,322,517
Beginning Balance at Jun. 30, 2022	60,515			$ 40			256,908			(135)	(196,298)
Beginning Balance (in shares) at Jun. 30, 2022				39,719,572
Stock-based compensation	569						569
Issuance of common stock from exercise of stock options	139						139
Issuance of common stock from exercise of stock options (in shares)				51,005
Issuance of common stock, net of commissions and allocated fees, less issuance costs			$ 51,184			$ 14			$ 51,170
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)						14,252,670
Issuance of common stock from warrant exercise	5,890			$ 4			5,886
Issuance of common stock from warrant exercise (in shares)				4,299,270
Unrealized gains (losses) on available-for-sale marketable securities	(128)									(128)
Net loss	(8,266)										(8,266)
Ending Balance at Sep. 30, 2022	109,903			$ 58			314,672			(263)	(204,564)
Ending Balance (in shares) at Sep. 30, 2022				58,322,517
Beginning Balance at Dec. 31, 2022	107,459			$ 60			317,590			(122)	(210,069)
Beginning Balance (in shares) at Dec. 31, 2022				59,943,430
Stock-based compensation	1,713						1,713
Issuance of common stock from exercise of stock options	$ 73						73
Issuance of common stock from exercise of stock options (in shares)	143,789			143,789
Issuance of common stock, net of commissions and allocated fees, less issuance costs		1,671			$ 1			1,670
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)					750,000
Issuance of common stock from Employee Stock Purchase Plan	$ 33						33
Issuance of common stock from Employee Stock Purchase Plan (in share)				19,273
Issuance of common stock from pre-funded warrant exercise				$ 3			(3)
Issuance of common stock from pre-funded warrant exercise (in shares)				2,998,838
Unrealized gains (losses) on available-for-sale marketable securities	(95)									(95)
Net loss	(21,244)										(21,244)
Ending Balance at Sep. 30, 2023	89,610			$ 64			321,076			(217)	(231,313)
Ending Balance (in shares) at Sep. 30, 2023				63,855,330
Beginning Balance at Jun. 30, 2023	95,073			$ 63			318,873			(248)	(223,615)
Beginning Balance (in shares) at Jun. 30, 2023				63,098,455
Stock-based compensation	530						530
Issuance of common stock from exercise of stock options	3						3
Issuance of common stock from exercise of stock options (in shares)				6,875
Issuance of common stock, net of commissions and allocated fees, less issuance costs		$ 1,671			$ 1			$ 1,670
Issuance of common stock, net of commissions and allocated fees, less issuance costs (in shares)					750,000
Unrealized gains (losses) on available-for-sale marketable securities	31									31
Net loss	(7,698)										(7,698)
Ending Balance at Sep. 30, 2023	$ 89,610			$ 64			$ 321,076			$ (217)	$ (231,313)
Ending Balance (in shares) at Sep. 30, 2023				63,855,330

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities:
Net loss	$ (21,244)	$ (23,647)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,713	1,826
Operating lease right-of-use assets	259	100
Accretion/accrual of term loan discounts and debt issuance costs	180	419
Depreciation and amortization	88	28
Loss on disposal of property, equipment and leasehold improvements	10
Accretion of available-for-sale marketable securities, net	(1,774)	(268)
Change in fair value of term loan derivative liability		147
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,935)	(579)
Accounts payable	(1,676)	(527)
Accrued expenses and other liabilities	28	657
Net cash used in operating activities	(25,351)	(21,844)
Investing activities:
Proceeds from maturities of available-for-sale marketable securities	55,679	2,001
Purchases of available-for-sale marketable securities	(8,981)	(61,025)
Purchases of property, equipment and leasehold improvements	(115)	(43)
Net cash provided by (used in) investing activities	46,583	(59,067)
Financing activities:
Proceeds from at-the-market sales, net of commissions	1,710
Proceeds from exercises of stock options	73	139
Proceeds from employee stock purchase plan	33	23
Repayments of term loan, term loan final fee and prepayment premium	(9,409)	(4,083)
Payments of offering costs	(200)	(195)
Payments of finance lease	(63)
Proceeds from sale of common stock and warrants in public offering and private placement, net of issuance costs		103,010
Proceeds from exercises of warrants		11,782
Payments of financing costs of term loan		(21)
Net cash (used in) provided by financing activities	(7,856)	110,655
Net increase in cash and cash equivalents	13,376	29,744
Cash and cash equivalents at beginning of period	12,589	36,830
Cash and cash equivalents at end of period	$ 25,965	$ 66,574

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2023
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 idiopathic pulmonary fibrosis (“IPF”) and refractory chronic cough 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 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited interim Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2023 and 2022 included herein have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim information. Certain information and footnote disclosures typically prepared in accordance with GAAP have been condensed or omitted pursuant to SEC rules and regulations. The accompanying unaudited Condensed Consolidated Financial Statements and notes should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Certain prior year balances have been reclassified to conform to the current year presentation. Such reclassifications did not affect loss from operations or net loss. The accompanying Condensed Consolidated Financial Statements include the accounts of Trevi Therapeutics, Inc. and its wholly-owned subsidiary Trevi Therapeutics Limited. Intercompany balances and transactions have been eliminated. All amounts presented are in thousands of dollars, except share and per share amounts, unless noted otherwise. The Company has evaluated events occurring subsequent to September 30, 2023 for potential recognition or disclosure in the Condensed Consolidated Financial Statements and concluded there were no subsequent events that required recognition or disclosure. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of the expenses during the reporting periods. Significant estimates and assumptions reflected in these Condensed Consolidated Financial Statements include but are not limited to the recognition of research and development (“R&D”) expenses, the valuation of stock-based awards and the valuation allowance of deferred tax assets. 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. Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheet as of September 30, 2023, the Condensed Consolidated Statements of Comprehensive Loss and the Condensed Consolidated Statements of Stockholders’ Equity for the three and nine months ended September 30, 2023 and 2022 and the Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2023 and 2022 are unaudited. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the Company’s opinion, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statements of its financial position as of September 30, 2023 and the results of its operations and its cash flows for the three and nine months ended September 30, 2023 and 2022. The results for the three and nine months ended September 30, 2023 and 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2023 or any other interim period or any future year or period. Cash Equivalents The Company classifies short-term, highly liquid investments with an original term of three months or less at the date of purchase as cash equivalents. Marketable Securities The Company generally invests its excess cash in money market funds and investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents or marketable securities on the Condensed Consolidated Balance Sheets. Marketable securities with an original maturity date greater than 90 days at each balance sheet date are classified as short-term. Marketable securities are 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 Condensed Consolidated Statements of Comprehensive Loss. Realized gains and losses and declines in value judged to be other than temporary, if any, on marketable securities are included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. The cost of securities sold is determined using specific identification. The Company evaluates whether declines in the fair values of its marketable securities below their amortized cost are other than temporary on a quarterly basis. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the marketable security or whether it is more likely than not that it will be required to sell any marketable securities before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the marketable security. Fair Value Measurements The Company’s financial instruments have consisted of cash and cash equivalents, available-for-sale marketable securities, other current assets, accounts payable, accrued expenses, term loans 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. government agency obligations, corporate bonds, commercial paper, asset-backed securities 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). Foreign Currency Transactions The Company, at times, contracts with vendors and consultants outside of the U.S., resulting in liabilities denominated in foreign currency. The transactions are recorded in U.S. dollars on the transaction dates and any currency fluctuation through the payment date is recorded as currency gains or losses in the Condensed Consolidated Statements of Comprehensive Loss. Deferred Offering Costs The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the financings. Should the planned equity financing no longer be considered probable of being consummated, the deferred offering costs are expensed immediately as a charge to general and administrative expenses. The deferred offering costs are included in Other current and non-current assets on the Condensed Consolidated Balance Sheets. Research and Development (“R&D”) Expenses All of the Company’s R&D expenses consist of expenses incurred in connection with the development of Haduvio. These expenses include certain payroll and personnel expenses, including stock-based compensation, consulting costs, contract manufacturing costs and fees paid to contract research organizations (“CROs”) to conduct certain R&D activities on the Company’s behalf. The Company expenses both internal and external R&D expenses as they are incurred. Accrued R&D Expenses The Company has entered into agreements with CROs, contract manufacturing organizations (“CMOs”) and other companies that provide services in connection with the Company’s R&D activities. The Company’s R&D accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events and contracted costs. The estimated costs of R&D provided, but not yet invoiced, are included in accrued expenses on the Condensed Consolidated Balance Sheets. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CROs, CMOs and other companies under these arrangements in advance of the performance of the related services are recorded as prepaid expenses or as other non-current assets, as applicable, and are recognized as expenses as the goods are delivered or the related services are performed. Patent Costs All patent-related costs in connection with filing and prosecuting patent applications are expensed to general and administrative expense as incurred, as recoverability of such expenditures is uncertain. Warrants The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480, Distinguishing Liabilities from Equity (“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 Taxes (“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 Condensed 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 September 30, 2023 and December 31, 2022 . 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. Leases are classified as either operating or finance, based on the Company’s evaluation of certain criteria. If a lease has a term greater than one year, the lease is recognized in the balance sheet as a right-of-use asset and a lease liability at lease commencement. The Company elected the short-term lease practical expedient, therefore, if a lease has a term less than one year, the Company will not recognize the lease on its balance sheet. The right-of-use asset represents the Company’s right of use to an underlying asset for the term of the lease and the liability represents the Company’s obligation to make lease payments arising from the lease. If 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. 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. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease, and right-of-use assets are subsequently re-measured to reflect the effect of uneven lease payments. For finance leases, right-of-use assets are amortized on a straight-line basis over the shorter of the lease term or the useful life of the underlying asset. Expenses for finance leases include the amortization of right-of-use assets, which is recorded as depreciation and amortization expense, and interest expense, which reflects interest accrued on the lease liability. 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 nine months ended September 30, 2023. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the nine months ended September 30, 2023 , which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements.

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2023
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 September 30, 2023 and December 31, 2022 are presented in the following table (in thousands): September 30, 2023 Type of security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate bonds $ 54,152 $ 18 $ ( 218 ) $ 53,952 U.S. government agency securities 4,993 — ( 15 ) 4,978 Commercial paper 1,994 — — 1,994 Asset backed securities 1,981 — ( 2 ) 1,979 Total marketable securities $ 63,120 $ 18 $ ( 235 ) $ 62,903 December 31, 2022 Type of Security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate bonds $ 62,573 $ 83 $ ( 143 ) $ 62,513 Commercial paper 30,739 — — 30,739 U.S. treasury securities 9,914 — ( 62 ) 9,852 U.S. government agency securities 2,905 2 ( 4 ) 2,903 Asset backed securities 1,912 2 — 1,914 Total marketable securities $ 108,043 $ 87 $ ( 209 ) $ 107,921 The net amortized cost and fair value of available-for-sale marketable securities at September 30, 2023 and December 31, 2022, respectively, are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company may intend to sell a security prior to maturity. September 30, 2023 Amortized Cost Fair Value Due to mature: Less than one year $ 57,666 $ 57,469 One year through two years 5,454 5,434 Total $ 63,120 $ 62,903 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 three and nine months ended September 30, 2023 and 2022 , there were no realized gains or losses on available-for-sale marketable securities.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
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 September 30, 2023 and December 31, 2022, 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 September 30, 2023 Financial assets: Cash equivalents Money market funds $ 25,715 $ — $ — $ 25,715 Marketable securities Corporate bonds — 53,952 — 53,952 Marketable securities U.S. government agency securities — 4,978 — 4,978 Marketable securities Commercial paper — 1,994 — 1,994 Marketable securities Asset backed securities — 1,979 — 1,979 Total assets $ 25,715 $ 62,903 $ — $ 88,618 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 Corporate bonds — 62,513 — 62,513 Marketable securities Commercial paper — 30,739 — 30,739 Marketable securities U.S. treasury securities 9,852 — — 9,852 Marketable securities U.S. government agency securities — 2,903 — 2,903 Marketable securities Asset backed securities — 1,914 — 1,914 Total assets $ 21,441 $ 98,069 $ — $ 119,510

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	5. Leases The Company entered into a lease for office space in New Haven, Connecticut, effective March 1, 2013, and entered into a First Amendment (the “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 approximated 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 received two designated months of free rent. As a result of the Company entering into the Second Amendment, the leased space increased 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 requires monthly payments ranging from approximately $ 23 to $ 32 effective in March 2023 through February 2028 . The first year of payments are based on 10,500 square feet of occupied space, the second year of payments are based on 11,500 square feet of occupied space and the remaining lease payments are based on 12,500 square feet of occupied space. In December 2022, the Company entered into a 24 -month lease for the financing of the furniture installed in the Company’s new office space. The furniture lease requires monthly payments of approximately $ 11 starting in March 2023. The Company also entered into an immaterial office equipment lease during 2022 that has a term of 36 months. The following table presents the Company’s lease-related assets and liabilities as of September 30, 2023 and December 31, 2022: Classification on the Condensed Consolidated Balance Sheet September 30, 2023 December 31, 2022 Assets: Operating lease assets Operating lease right-of-use assets $ 1,190 $ 24 Finance lease assets Finance lease right-of-use assets 218 — Total lease assets $ 1,408 $ 24 Liabilities: Current Operating lease liabilities Operating lease liabilities, current portion $ 171 $ 25 Finance lease liabilities Finance lease liabilities, current portion 121 — Non-current Operating lease liabilities Operating lease liabilities, non-current portion 1,051 2 Finance lease liabilities Finance lease liabilities, non-current portion 62 — Total lease liabilities $ 1,405 $ 27 The following table presents information related to the Company’s lease expense for the three and nine months ended September 30, 2023 and 2022: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Operating lease expense $ 85 $ 31 $ 202 $ 92 Finance lease expense 12 — 24 — Total lease expense $ 97 $ 31 $ 226 $ 92 Future minimum lease payments from September 30, 2023 until the expiration of the leases are as follows: Operating Leases Finance Leases 2023 $ 69 $ 32 2024 303 126 2025 349 32 2026 368 — 2027 377 — Thereafter 95 — Total minimum lease payments 1,561 190 Less: Amount of lease payments representing interest ( 339 ) ( 7 ) Present value of future minimum lease payments $ 1,222 $ 183 The following table presents certain information related to the lease terms and discount rates for the Company’s leases as of September 30, 2023 and December 31, 2022: September 30, 2023 December 31, 2022 Weighted average remaining lease term: Operating leases 4.5 years 0.3 years Finance leases 1.5 years not applicable Weighted average discount rate: Operating leases 11.00 % 13.00 % Finance leases 4.37 % not applicable The following table presents supplemental cash flow information related to the Company’s leases for the three and nine months ended September 30, 2023 and 2022: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows relating to operating leases $ 69 $ 36 $ 162 $ 95 Finance lease payments $ 32 $ — $ 63 $ — Supplemental non-cash information: Right-of-use assets obtained in exchange for new operating lease liabilities $ — $ 4 $ 1,289 $ 4 Right-of-use assets obtained in exchange for new finance lease liabilities $ — $ — $ 242 $ —

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following: September 30, 2023 December 31, 2022 Accrued R&D projects $ 1,842 $ 1,130 Accrued compensation and benefits 1,221 1,508 Accrued consulting and professional fees 490 382 Accrued other 72 498 Total accrued expenses $ 3,625 $ 3,518

Debt

Debt	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt	7. Debt Silicon Valley Bank Term Loan On May 9, 2023, the Company paid the remaining amount due under the SVB Loan Agreement (as described below), resulting in the full extinguishment of the SVB Term Loan as described below. The total payoff amount was $ 6.5 million, consisting of the remaining principal amount due of $ 5.2 million, the final payment fee of $ 1.2 million, and $ 0.1 million of accrued interest and prepayment premium. On March 10, 2023, Silicon Valley Bank (“SVB”) was closed by the California Department of Financial Protection and Innovation and the Federal Deposit Insurance Corporation (“FDIC”) was appointed as receiver. While SVB was the Company’s primary bank at the time of its closure, the vast majority of the Company’s total cash, cash equivalents and marketable securities resided in custodial accounts held by U.S. Bank for which SVB Asset Management was the advisor. The FDIC subsequently transferred all of SVB’s deposits and loans to a newly created bridge bank, named Silicon Valley Bridge Bank, N.A., under a systemic risk exception approved by the United States Department of the Treasury, the Board of Governors of the Federal Reserve, and the FDIC. On March 27, 2023, First Citizens Bank & Trust Company (“First Citizens Bank”) assumed all of SVB’s deposits and certain other liabilities and acquired substantially all of SVB’s loans and certain other assets from the FDIC. As a result, all of the Company’s deposits that were at SVB and the Company’s SVB Term Loan were then moved to First Citizens Bank. The Company has access to all cash, cash equivalents and marketable securities that had been in its SVB accounts, and does not expect losses or material disruptions to the Company’s ongoing operations due to SVB’s closure. On August 13, 2020 (the “Effective Date”), the Company entered into a loan and security agreement (the “SVB Loan Agreement”) with SVB, as lender, 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 bore 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 were due and payable in full on February 1, 20 24 . The SVB Loan Agreement permitted voluntary prepayment of all, but not less than all, of the SVB Term Loan, subject to a prepayment premium. Such prepayment premium would have been 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 was required to pay a final payment fee equal to $ 1.2 million. The SVB Term Loan and related obligations under the SVB Loan Agreement were secured by substantially all of the Company’s properties, rights and assets, except for its intellectual property (which was 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 have been 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 have been 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 have been 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 at-the-market (“ATM”) Sales Agreement entered into with SVB Securities LLC (formerly SVB Leerink LLC) (“SVB Securities”) in June 2020 (the “ATM Sales Agreement”) and two private placements, which took place in October 2021 (see Note 8). On April 6, 2022, the Company and SVB entered into a Third Amendment (the “Third Amendment”) to the SVB Loan Agreement. The Third Amendment principally modified the conditions under which the Company would have been 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 have terminated and the sole remaining trigger for cash collateralization would have been 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 IPF. In addition, the Third Amendment modified the interest rate on the principal amount outstanding under the SVB Loan Agreement. As a result of the Third Amendment, amounts outstanding under the SVB Loan Agreement accrued 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 contained customary representations, warranties, events of default and covenants. The occurrence and continuation of an event of default could have caused interest to be charged at the rate that was otherwise applicable plus 5.00 % (unless SVB elected to impose a smaller increase) and would have provided 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 restricted 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 were 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 were amortized over the 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 were amortized over the life of the SVB Term Loan using the effective interest method. 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 were included as a reduction in the balance of the term loan payable on the Company’s Condensed Consolidated Balance Sheets and were accreted over the life of the SVB Term Loan using the effective interest method. In connection with the SVB Loan Agreement, the Company was obligated to pay a final payment fee of $ 1.2 million upon repayment in full of the SVB Term Loan. The final payment fee was accrued over the life of the SVB Term Loan using the effective interest method and was included as an increase in the balance of the term loan payable on the Company’s Condensed Consolidated Balance Sheets. The Company paid this final payment fee of $ 1.2 million on May 9, 2023 in connection with the payoff in full of the SVB Term Loan. 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 Condensed Consolidated Statements of Comprehensive Loss. The term loan derivative liability was previously presented as a current liability on the Company’s Condensed Consolidated Balance Sheets. Upon recording such term loan derivative liability, the Company also recorded an offsetting term loan discount – interest, that was amortized to interest expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss through the SVB Term Loan’s maturity date using the effective interest method. 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 in 2022. The term loan derivative liability was then settled and reclassified to both current and non-current interest payable, which were presented as accrued liabilities and other non-current liabilities on the Company’s Condensed Consolidated Balance Sheet. During the nine months ended September 30, 2023, an immaterial effect from early extinguishment of debt was recorded in connection with the Company paying the remaining amounts due under the SVB Loan Agreement, which was included in other income, net on the Company’s Condensed Consolidated Statements of Comprehensive Loss. As of September 30, 2023 , the Company had no outstanding borrowings, and as of December 31, 2022, the Company had outstanding borrowings of $ 8.2 million under the SVB Term Loan. The term loan payable balance as presented on the Company’s Condensed Consolidated Balance Sheets as of September 30, 2023 was $ 0 and as of December 31, 2022 was as shown below. December 31, 2022 Principal outstanding under term loan $ 8,167 Term loan discount-interest ( 24 ) Term loan discount-unamortized deferred charges ( 29 ) Term loan discount-financing costs, net of accretion ( 3 ) Term loan-final payment fee 1,040 9,151 Less current portion 7,000 Term loan payable, non-current $ 2,151 Interest expense on the SVB Term Loan, which is comprised of interest payments, accretion and amortization of term loan discounts and the accrual of the final payment fee, is shown below for the three and nine months ended September 30, 2023 and 2022, respectively. For the three and nine months ended September 30, 2022 , the weighted average interest rate applicable to borrowings under the SVB Term Loan was 6.97 % and 5.27 %, respectively. For the nine months ended September 30, 2023 , the weighted average interest rate applicable to borrowings under the SVB Term Loan was 10.25 %. Three Months Ended Nine Months Ended 2023 2022 2023 2022 Interest payments $ — $ 170 $ 202 $ 470 Accrual of the final payment fee — 89 150 309 Accretion and amortization of term loan discounts — 33 30 110 $ — $ 292 $ 382 $ 889

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Stockholders' Equity	8. Stockholders’ Equity As of September 30, 2023 and December 31, 2022, the Company had reserved shares of common stock for future issuance as shown in the table below: September 30, December 31, Shares of common stock reserved for future issuance upon exercise of outstanding warrants and pre-funded warrants 45,330,707 48,330,707 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 6,549,024 4,553,202 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 1,208,274 701,232 Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 568,243 602,231 Shares of common stock reserved for future issuance upon sales under the LPC Purchase Agreement — 30,000,000 53,656,248 84,187,372 At-the-Market Offering In June 2020, the Company entered into the ATM Sales Agreement with SVB Securities under which the Company was able to issue and sell shares of its common stock, from time to time, having an aggregate offering price of up to $ 12.0 million. In May 2022, the Company and SVB Securities amended the ATM Sales Agreement to increase the maximum aggregate offering price of common stock that it was able to 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. Sales of common stock under the ATM Sales Agreement were able to be made by any method that was deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended. The Company was 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. As of September 30, 2023 , the Company had issued and sold an aggregate of 4,333,394 shares of common stock for gross proceeds of $ 12.7 million pursuant to the ATM Sales Agreement, before deducting estimated commissions and allocated fees of $ 1.0 million. In June 2023, the Company filed with the SEC a universal shelf registration statement on Form S-3 (the “Shelf Registration Statement”), which allows the Company to offer and sell up to $ 200.0 million of common stock, preferred stock, debt securities, units and/or warrants from time to time pursuant to one or more offerings at prices and terms to be determined at the time of sale. The Shelf Registration Statement was filed to replace the Company’s prior universal shelf registration statement on Form S-3 and was declared effective on August 15, 2023. Further, in June 2023, the Company entered into a new ATM sales agreement with Leerink Partners, LLC (formerly SVB Securities) (the “New ATM Sales Agreement”), under which the Company may issue and sell shares of common stock, from time to time 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 New ATM Sales Agreement. The Company filed a prospectus under the Shelf Registration Statement for the offer and sale of shares of the Company’s common stock having an aggregate offering price of up to $ 75.0 million pursuant to the New ATM Sales Agreement. In accordance with the terms of the New ATM Sales Agreement, the ATM Sales Agreement terminated upon effectiveness of the Shelf Registration Statement, at which point the Company was no longer able to issue and sell shares of its common stock under the ATM Sales Agreement. As of September 30, 2023, the Company had not made any sales pursuant to the New ATM Sales Agreement. 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 provided that, subject to the terms and conditions therein, the Company had 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. 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. As of July 23, 2023, no shares had been sold to Lincoln Park and the LPC Purchase Agreement terminated by its terms. 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 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 nine months ended September 30, 2023, is shown in the table below: Number of Number of Total Number of Weighted Outstanding as of December 31, 2022 38,627,003 9,703,704 48,330,707 $ 0.28 Exercised ( 3,000,000 ) — ( 3,000,000 ) $ 0.001 Outstanding as of September 30, 2023 35,627,003 9,703,704 45,330,707 $ 0.29 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 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 7,117,267 as of September 30, 2023, of which 1,801,724 shares remained available for grant under the 2019 Plan. Awards may be made under the 2019 Plan for up to such number of shares of the Company’s common stock as is equal to the sum of: i) 1,578,947 shares; plus ii) the number of shares (up to 1,157,894 shares) 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, 2023 and January 1, 2022, respectively, the number of shares reserved for issuance under the 2019 Plan increased, pursuant to the terms of the 2019 Plan, by an additional 2,105,623 shares and 1,140,232 shares, equal to the 2019 Plan determined maximum and 4 % of the Company’s then-outstanding common stock, respectively. 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 September 30, 2023 and December 31, 2022 , respectively, options to purchase 4,747,300 shares and 3,848,052 shares of common stock were granted and outstanding, net of cancellations, under the 2019 Plan. As of September 30, 2023 and December 31, 2022 , respectively, options to purchase 568,243 and 602,231 shares of common stock were granted and outstanding, net of cancellations, under the 2012 Plan. A summary of the Company’s combined stock option activity for the 2019 Plan and the 2012 Plan for the nine months ended September 30, 2023 is as follows: Number of Weighted Outstanding as of December 31, 2022 4,450,283 $ 3.26 Granted 1,562,000 $ 2.62 Forfeited ( 318,075 ) $ 1.77 Expired ( 234,876 ) $ 3.23 Exercised ( 143,789 ) $ 0.51 Outstanding as of September 30, 2023 5,315,543 $ 3.24 Options exercisable as of September 30, 2023 2,607,790 $ 4.32 Options unvested as of September 30, 2023 2,707,753 $ 2.20 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 1,208,274 as of September 30, 2023 . 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, 2023 and January 1, 2022 , 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 526,315 shares and 285,058 shares, equal to the 2019 ESPP determined maximum and 1 % of the Company’s then-outstanding common stock, respectively . The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan, the 2019 Plan and the 2019 ESPP recognized in the Condensed Consolidated Statements of Comprehensive Loss: Three Months Ended Nine Months Ended 2023 2022 2023 2022 General and administrative expense $ 319 $ 371 $ 1,056 $ 1,195 Research and development expense 211 198 657 631 $ 530 $ 569 $ 1,713 $ 1,826

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes As of September 30, 2023 and December 31, 2022, the Company maintained a full valuation allowance on deferred tax assets. The income tax benefit recorded during the three and nine months ended September 30, 2023 and 2022 was for the Company ’ s estimates for its state research and development tax credits in each given year.

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Loss per Share	10. Net Loss per Share The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Net loss $ ( 7,698 ) $ ( 8,266 ) $ ( 21,244 ) $ ( 23,647 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 99,325,540 68,898,810 98,880,882 53,221,949 Basic and diluted net loss per common share outstanding $ ( 0.08 ) $ ( 0.12 ) $ ( 0.21 ) $ ( 0.44 ) 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 September 30, 2023 , the Company had pre-funded warrants to purchase 21,379,673 and 14,247,330 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 three and nine months ended September 30, 2023 and 2022, respectively. 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 September 30, 2023 and 2022, 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 September 30, 2023 2022 Warrants 9,703,704 9,703,704 Stock Options 5,315,543 4,141,907 15,019,247 13,845,611

Collaborative and Licensing Agr

Collaborative and Licensing Agreements	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative and Licensing Agreements	11. 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	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies A significant portion of the Company’s development activities are outsourced to third parties under agreements, including with CROs and contract manufacturers in connection with the production of clinical trial materials. These arrangements may require the Company to pay termination costs to the third parties for reimbursement of costs and expenses incurred in the event of the orderly termination of contractual services. The Company also has commitments under lease and licensing agreements (Note 5 and Note 11).

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2023 and 2022 included herein have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim information. Certain information and footnote disclosures typically prepared in accordance with GAAP have been condensed or omitted pursuant to SEC rules and regulations. The accompanying unaudited Condensed Consolidated Financial Statements and notes should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Certain prior year balances have been reclassified to conform to the current year presentation. Such reclassifications did not affect loss from operations or net loss. The accompanying Condensed Consolidated Financial Statements include the accounts of Trevi Therapeutics, Inc. and its wholly-owned subsidiary Trevi Therapeutics Limited. Intercompany balances and transactions have been eliminated. All amounts presented are in thousands of dollars, except share and per share amounts, unless noted otherwise. The Company has evaluated events occurring subsequent to September 30, 2023 for potential recognition or disclosure in the Condensed Consolidated Financial Statements and concluded there were no subsequent events that required recognition or disclosure.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of the expenses during the reporting periods. Significant estimates and assumptions reflected in these Condensed Consolidated Financial Statements include but are not limited to the recognition of research and development (“R&D”) expenses, the valuation of stock-based awards and the valuation allowance of deferred tax assets. 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.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim Condensed Consolidated Balance Sheet as of September 30, 2023, the Condensed Consolidated Statements of Comprehensive Loss and the Condensed Consolidated Statements of Stockholders’ Equity for the three and nine months ended September 30, 2023 and 2022 and the Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2023 and 2022 are unaudited. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the Company’s opinion, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statements of its financial position as of September 30, 2023 and the results of its operations and its cash flows for the three and nine months ended September 30, 2023 and 2022. The results for the three and nine months ended September 30, 2023 and 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2023 or any other interim period or any future year or period.
Cash Equivalents	Cash Equivalents The Company classifies short-term, highly liquid investments with an original term of three months or less at the date of purchase as cash equivalents.
Marketable Securities	Marketable Securities The Company generally invests its excess cash in money market funds and investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents or marketable securities on the Condensed Consolidated Balance Sheets. Marketable securities with an original maturity date greater than 90 days at each balance sheet date are classified as short-term. Marketable securities are 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 Condensed Consolidated Statements of Comprehensive Loss. Realized gains and losses and declines in value judged to be other than temporary, if any, on marketable securities are included in interest income, net on the Condensed Consolidated Statements of Comprehensive Loss. The cost of securities sold is determined using specific identification. The Company evaluates whether declines in the fair values of its marketable securities below their amortized cost are other than temporary on a quarterly basis. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the marketable security or whether it is more likely than not that it will be required to sell any marketable securities before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the marketable security, duration and severity of the decline in value, and the Company’s strategy and intentions for holding the marketable security.
Fair Value Measurements	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 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. government agency obligations, corporate bonds, commercial paper, asset-backed securities 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).
Foreign Currency Transactions	Foreign Currency Transactions The Company, at times, contracts with vendors and consultants outside of the U.S., resulting in liabilities denominated in foreign currency. The transactions are recorded in U.S. dollars on the transaction dates and any currency fluctuation through the payment date is recorded as currency gains or losses in the Condensed Consolidated Statements of Comprehensive Loss.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the financings. Should the planned equity financing no longer be considered probable of being consummated, the deferred offering costs are expensed immediately as a charge to general and administrative expenses. The deferred offering costs are included in Other current and non-current assets on the Condensed Consolidated Balance Sheets.
Research and Development ("R&D") Expenses	Research and Development (“R&D”) Expenses All of the Company’s R&D expenses consist of expenses incurred in connection with the development of Haduvio. These expenses include certain payroll and personnel expenses, including stock-based compensation, consulting costs, contract manufacturing costs and fees paid to contract research organizations (“CROs”) to conduct certain R&D activities on the Company’s behalf. The Company expenses both internal and external R&D expenses as they are incurred.
Accrued R&D Expenses	Accrued R&D Expenses The Company has entered into agreements with CROs, contract manufacturing organizations (“CMOs”) and other companies that provide services in connection with the Company’s R&D activities. The Company’s R&D accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events and contracted costs. The estimated costs of R&D provided, but not yet invoiced, are included in accrued expenses on the Condensed Consolidated Balance Sheets. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CROs, CMOs and other companies under these arrangements in advance of the performance of the related services are recorded as prepaid expenses or as other non-current assets, as applicable, and are recognized as expenses as the goods are delivered or the related services are performed.
Patent Costs	Patent Costs All patent-related costs in connection with filing and prosecuting patent applications are expensed to general and administrative expense as incurred, as recoverability of such expenditures is uncertain.
Warrants	Warrants The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480, Distinguishing Liabilities from Equity (“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 Taxes (“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 Condensed 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 September 30, 2023 and December 31, 2022 . 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. Leases are classified as either operating or finance, based on the Company’s evaluation of certain criteria. If a lease has a term greater than one year, the lease is recognized in the balance sheet as a right-of-use asset and a lease liability at lease commencement. The Company elected the short-term lease practical expedient, therefore, if a lease has a term less than one year, the Company will not recognize the lease on its balance sheet. The right-of-use asset represents the Company’s right of use to an underlying asset for the term of the lease and the liability represents the Company’s obligation to make lease payments arising from the lease. If 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. 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. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease, and right-of-use assets are subsequently re-measured to reflect the effect of uneven lease payments. For finance leases, right-of-use assets are amortized on a straight-line basis over the shorter of the lease term or the useful life of the underlying asset. Expenses for finance leases include the amortization of right-of-use assets, which is recorded as depreciation and amortization expense, and interest expense, which reflects interest accrued on the lease liability.
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 nine months ended September 30, 2023. Recently Issued Accounting Pronouncements There have been no new pronouncements issued during the nine months ended September 30, 2023 , which could be expected to materially impact the Company’s Condensed Consolidated Financial Statements.

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2023
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 September 30, 2023 and December 31, 2022 are presented in the following table (in thousands): September 30, 2023 Type of security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate bonds $ 54,152 $ 18 $ ( 218 ) $ 53,952 U.S. government agency securities 4,993 — ( 15 ) 4,978 Commercial paper 1,994 — — 1,994 Asset backed securities 1,981 — ( 2 ) 1,979 Total marketable securities $ 63,120 $ 18 $ ( 235 ) $ 62,903 December 31, 2022 Type of Security Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Corporate bonds $ 62,573 $ 83 $ ( 143 ) $ 62,513 Commercial paper 30,739 — — 30,739 U.S. treasury securities 9,914 — ( 62 ) 9,852 U.S. government agency securities 2,905 2 ( 4 ) 2,903 Asset backed securities 1,912 2 — 1,914 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 September 30, 2023 and December 31, 2022, respectively, are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company may intend to sell a security prior to maturity. September 30, 2023 Amortized Cost Fair Value Due to mature: Less than one year $ 57,666 $ 57,469 One year through two years 5,454 5,434 Total $ 63,120 $ 62,903 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)	9 Months Ended
	Sep. 30, 2023
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 September 30, 2023 and December 31, 2022, 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 September 30, 2023 Financial assets: Cash equivalents Money market funds $ 25,715 $ — $ — $ 25,715 Marketable securities Corporate bonds — 53,952 — 53,952 Marketable securities U.S. government agency securities — 4,978 — 4,978 Marketable securities Commercial paper — 1,994 — 1,994 Marketable securities Asset backed securities — 1,979 — 1,979 Total assets $ 25,715 $ 62,903 $ — $ 88,618 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 Corporate bonds — 62,513 — 62,513 Marketable securities Commercial paper — 30,739 — 30,739 Marketable securities U.S. treasury securities 9,852 — — 9,852 Marketable securities U.S. government agency securities — 2,903 — 2,903 Marketable securities Asset backed securities — 1,914 — 1,914 Total assets $ 21,441 $ 98,069 $ — $ 119,510

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Schedule of Lease-related Assets and Liabilities	The following table presents the Company’s lease-related assets and liabilities as of September 30, 2023 and December 31, 2022: Classification on the Condensed Consolidated Balance Sheet September 30, 2023 December 31, 2022 Assets: Operating lease assets Operating lease right-of-use assets $ 1,190 $ 24 Finance lease assets Finance lease right-of-use assets 218 — Total lease assets $ 1,408 $ 24 Liabilities: Current Operating lease liabilities Operating lease liabilities, current portion $ 171 $ 25 Finance lease liabilities Finance lease liabilities, current portion 121 — Non-current Operating lease liabilities Operating lease liabilities, non-current portion 1,051 2 Finance lease liabilities Finance lease liabilities, non-current portion 62 — Total lease liabilities $ 1,405 $ 27
Schedule of Information Related to Lease Expense	The following table presents information related to the Company’s lease expense for the three and nine months ended September 30, 2023 and 2022: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Operating lease expense $ 85 $ 31 $ 202 $ 92 Finance lease expense 12 — 24 — Total lease expense $ 97 $ 31 $ 226 $ 92
Schedule of Future Lease Payments of Leases	Future minimum lease payments from September 30, 2023 until the expiration of the leases are as follows: Operating Leases Finance Leases 2023 $ 69 $ 32 2024 303 126 2025 349 32 2026 368 — 2027 377 — Thereafter 95 — Total minimum lease payments 1,561 190 Less: Amount of lease payments representing interest ( 339 ) ( 7 ) Present value of future minimum lease payments $ 1,222 $ 183
Schedule of Information Related to the Lease Terms and Discount Rates of Leases	The following table presents certain information related to the lease terms and discount rates for the Company’s leases as of September 30, 2023 and December 31, 2022: September 30, 2023 December 31, 2022 Weighted average remaining lease term: Operating leases 4.5 years 0.3 years Finance leases 1.5 years not applicable Weighted average discount rate: Operating leases 11.00 % 13.00 % Finance leases 4.37 % not applicable
Schedule of Supplemental Cash Flow Information Related to Leases	The following table presents supplemental cash flow information related to the Company’s leases for the three and nine months ended September 30, 2023 and 2022: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows relating to operating leases $ 69 $ 36 $ 162 $ 95 Finance lease payments $ 32 $ — $ 63 $ — Supplemental non-cash information: Right-of-use assets obtained in exchange for new operating lease liabilities $ — $ 4 $ 1,289 $ 4 Right-of-use assets obtained in exchange for new finance lease liabilities $ — $ — $ 242 $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: September 30, 2023 December 31, 2022 Accrued R&D projects $ 1,842 $ 1,130 Accrued compensation and benefits 1,221 1,508 Accrued consulting and professional fees 490 382 Accrued other 72 498 Total accrued expenses $ 3,625 $ 3,518

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowings under SVB Term Loan	As of September 30, 2023 , the Company had no outstanding borrowings, and as of December 31, 2022, the Company had outstanding borrowings of $ 8.2 million under the SVB Term Loan. The term loan payable balance as presented on the Company’s Condensed Consolidated Balance Sheets as of September 30, 2023 was $ 0 and as of December 31, 2022 was as shown below. December 31, 2022 Principal outstanding under term loan $ 8,167 Term loan discount-interest ( 24 ) Term loan discount-unamortized deferred charges ( 29 ) Term loan discount-financing costs, net of accretion ( 3 ) Term loan-final payment fee 1,040 9,151 Less current portion 7,000 Term loan payable, non-current $ 2,151
Schedule of Components of Interest Expense of Term Loan	Interest expense on the SVB Term Loan, which is comprised of interest payments, accretion and amortization of term loan discounts and the accrual of the final payment fee, is shown below for the three and nine months ended September 30, 2023 and 2022, respectively. For the three and nine months ended September 30, 2022 , the weighted average interest rate applicable to borrowings under the SVB Term Loan was 6.97 % and 5.27 %, respectively. For the nine months ended September 30, 2023 , the weighted average interest rate applicable to borrowings under the SVB Term Loan was 10.25 %. Three Months Ended Nine Months Ended 2023 2022 2023 2022 Interest payments $ — $ 170 $ 202 $ 470 Accrual of the final payment fee — 89 150 309 Accretion and amortization of term loan discounts — 33 30 110 $ — $ 292 $ 382 $ 889

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Reserved for Future Issuance	As of September 30, 2023 and December 31, 2022, the Company had reserved shares of common stock for future issuance as shown in the table below: September 30, December 31, Shares of common stock reserved for future issuance upon exercise of outstanding warrants and pre-funded warrants 45,330,707 48,330,707 Shares of common stock reserved for future issuance under the 2019 Stock Incentive Plan 6,549,024 4,553,202 Shares of common stock reserved for future issuance under the 2019 Employee Stock Purchase Plan 1,208,274 701,232 Shares of common stock reserved for future issuance under the 2012 Stock Incentive Plan 568,243 602,231 Shares of common stock reserved for future issuance upon sales under the LPC Purchase Agreement — 30,000,000 53,656,248 84,187,372
Warrant Activity Including Activity Related To Pre-funded Warrants	Warrant activity, including activity related to pre-funded warrants, for the nine months ended September 30, 2023, is shown in the table below: Number of Number of Total Number of Weighted Outstanding as of December 31, 2022 38,627,003 9,703,704 48,330,707 $ 0.28 Exercised ( 3,000,000 ) — ( 3,000,000 ) $ 0.001 Outstanding as of September 30, 2023 35,627,003 9,703,704 45,330,707 $ 0.29
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 nine months ended September 30, 2023 is as follows: Number of Weighted Outstanding as of December 31, 2022 4,450,283 $ 3.26 Granted 1,562,000 $ 2.62 Forfeited ( 318,075 ) $ 1.77 Expired ( 234,876 ) $ 3.23 Exercised ( 143,789 ) $ 0.51 Outstanding as of September 30, 2023 5,315,543 $ 3.24 Options exercisable as of September 30, 2023 2,607,790 $ 4.32 Options unvested as of September 30, 2023 2,707,753 $ 2.20
Schedule of Stock-based Compensation Expenses Recognized	The following table summarizes the classifications of stock-based compensation expenses for the 2012 Plan, the 2019 Plan and the 2019 ESPP recognized in the Condensed Consolidated Statements of Comprehensive Loss: Three Months Ended Nine Months Ended 2023 2022 2023 2022 General and administrative expense $ 319 $ 371 $ 1,056 $ 1,195 Research and development expense 211 198 657 631 $ 530 $ 569 $ 1,713 $ 1,826

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Three Months Ended Nine Months Ended 2023 2022 2023 2022 Net loss $ ( 7,698 ) $ ( 8,266 ) $ ( 21,244 ) $ ( 23,647 ) Weighted average common shares used in net loss per share attributable to common stockholders, basic and diluted 99,325,540 68,898,810 98,880,882 53,221,949 Basic and diluted net loss per common share outstanding $ ( 0.08 ) $ ( 0.12 ) $ ( 0.21 ) $ ( 0.44 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potential common shares, presented based on shares outstanding as of September 30, 2023 and 2022, 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 September 30, 2023 2022 Warrants 9,703,704 9,703,704 Stock Options 5,315,543 4,141,907 15,019,247 13,845,611

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2023 USD ($) Segment
Summary Of Significant Accounting Policies [Line Items]
Dividends, common stock, cash | $	$ 0
Number of reporting segment	1
Number of operating segment	1
Computer Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Equipment and leasehold improvements, useful life	3 years
Furniture and Office Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, Equipment and leasehold improvements, useful life	5 years

Marketable Securities - Schedul

Marketable Securities - Schedule of Fair Value And Amortized Cost Of Available-for-sale Marketable Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	$ 63,120	$ 108,043
Gross Unrealized Gains	18	87
Gross Unrealized Losses	(235)	(209)
Estimated Fair Value	62,903	107,921
Corporate Bonds [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	54,152	62,573
Gross Unrealized Gains	18	83
Gross Unrealized Losses	(218)	(143)
Estimated Fair Value	53,952	62,513
Commercial Paper [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	1,994	30,739
Estimated Fair Value	1,994	30,739
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
U.S. Government Agency Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	4,993	2,905
Gross Unrealized Gains		2
Gross Unrealized Losses	(15)	(4)
Estimated Fair Value	4,978	2,903
Asset Backed Securities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Amortized Cost	1,981	1,912
Gross Unrealized Gains		2
Gross Unrealized Losses	(2)
Estimated Fair Value	$ 1,979	$ 1,914

Marketable Securities - Summary

Marketable Securities - Summary Of Contractual Maturities Of Available-for-sale Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Amortized cost, less than one year	$ 57,666	$ 69,527
Amortized cost, one year through two years	5,454	38,516
Amortized Cost	63,120	108,043
Fair value, less than one year	57,469	69,367
Fair Value, one year through two years	5,434	38,554
Fair Value	$ 62,903	$ 107,921

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Debt Securities, Available-for-Sale [Line Items]
Realized gains or losses on available-for-sale marketable securities	$ 0	$ 0	$ 0	$ 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	Sep. 30, 2023	Dec. 31, 2022
Financial assets:
Total assets	$ 88,618	$ 119,510
Corporate Bonds [Member]
Financial assets:
Marketable securities	53,952	62,513
Commercial Paper [Member]
Financial assets:
Marketable securities	1,994	30,739
U.S. Treasury Securities [Member]
Financial assets:
Marketable securities		9,852
U.S. Government Agency Securities [Member]
Financial assets:
Marketable securities	4,978	2,903
Asset Backed Securities [Member]
Financial assets:
Marketable securities	1,979	1,914
Level 1 [Member]
Financial assets:
Total assets	25,715	21,441
Level 1 [Member] | U.S. Treasury Securities [Member]
Financial assets:
Marketable securities		9,852
Level 2 [Member]
Financial assets:
Total assets	62,903	98,069
Level 2 [Member] | Corporate Bonds [Member]
Financial assets:
Marketable securities	53,952	62,513
Level 2 [Member] | Commercial Paper [Member]
Financial assets:
Marketable securities	1,994	30,739
Level 2 [Member] | U.S. Government Agency Securities [Member]
Financial assets:
Marketable securities	4,978	2,903
Level 2 [Member] | Asset Backed Securities [Member]
Financial assets:
Marketable securities	1,979	1,914
Money Market Funds [Member]
Financial assets:
Cash equivalents	25,715	11,589
Money Market Funds [Member] | Level 1 [Member]
Financial assets:
Cash equivalents	$ 25,715	$ 11,589

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands			3 Months Ended
	Nov. 21, 2022 USD ($) ft²	Dec. 05, 2017 USD ($) ft²	Mar. 31, 2023 USD ($)	Sep. 30, 2023 ft²	Dec. 31, 2022
Leases [Line Items]
First year of payments square feet of occupied space				10,500
Second year of payments square feet of occupied space				11,500
Remaining lease payments square feet of occupied space				12,500
Building [Member]
Leases [Line Items]
Leased spaced area	12,500	5,600
Lease expiration date	Feb. 28, 2028	Feb. 28, 2023
Operating lease term	60 months	60 months
Term of required monthly payments	2028-02
Building [Member] | Minimum [Member]
Leases [Line Items]
Operating lease rent expense | $	$ 23	$ 10
Building [Member] | Maximum [Member]
Leases [Line Items]
Operating lease rent expense | $	$ 32	$ 12
Furniture [Member]
Leases [Line Items]
Operating lease term					24 months
Operating lease rent expense | $			$ 11
Office Equipment [Member]
Leases [Line Items]
Operating lease term					36 months

Leases - Schedule of Lease-rela

Leases - Schedule of Lease-related Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Operating lease assets	$ 1,190	$ 24
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Operating lease assets	Operating lease assets
Finance lease assets	$ 218
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Finance lease assets	Finance lease assets
Total lease assets	$ 1,408	$ 24
Current
Operating lease liabilities	$ 171	$ 25
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Operating lease liabilities	Operating lease liabilities
Finance lease liabilities	$ 121
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Finance lease liabilities	Finance lease liabilities
Non-current
Operating lease liabilities	$ 1,051	$ 2
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Operating lease liabilities	Operating lease liabilities
Finance lease liabilities	$ 62
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Finance lease liabilities	Finance lease liabilities
Total lease liabilities	$ 1,405	$ 27

Leases - Schedule of Informatio

Leases - Schedule of Information Related to Lease Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Operating lease expense	$ 85	$ 31	$ 202	$ 92
Finance lease expense:	12		24
Total lease expense	$ 97	$ 31	$ 226	$ 92

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2023 USD ($)
Operating Leases
2023	$ 69
2024	303
2025	349
2026	368
2027	377
Thereafter	95
Total minimum lease payments	1,561
Less: Amount of lease payments representing interest	(339)
Present value of future minimum lease payments	1,222
Finance Leases
2023	32
2024	126
2025	32
Total minimum lease payments	190
Less: Amount of lease payments representing interest	(7)
Present value of future minimum lease payments	$ 183

Leases - Schedule of Informat_2

Leases - Schedule of Information Related to the Lease Terms and Discount Rates of Leases (Detail)	Sep. 30, 2023	Dec. 31, 2022
Weighted average remaining lease term:
Operating leases	4 years 6 months	3 months 18 days
Finance leases	1 year 6 months
Weighted average discount rate:
Operating leases	11%	13%
Finance leases	4.37%

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows relating to operating leases	$ 69	$ 36	$ 162	$ 95
Finance lease payments	$ 32		63
Supplemental non-cash information:
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 4	1,289	$ 4
Right-of-use assets obtained in exchange for new finance lease liabilities			$ 242

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued R&D projects	$ 1,842	$ 1,130
Accrued compensation and benefits	1,221	1,508
Accrued consulting and professional fees	490	382
Accrued other	72	498
Total accrued expenses	$ 3,625	$ 3,518

Debt - Additional Information (

Debt - Additional Information (Detail) $ in Thousands					1 Months Ended	3 Months Ended	5 Months Ended	9 Months Ended
	May 09, 2023 USD ($)	Apr. 06, 2022 USD ($)	Jul. 06, 2021 USD ($)	Aug. 13, 2020 USD ($) Installment	Oct. 31, 2021 PrivatePlacement	Sep. 30, 2022	Oct. 31, 2021 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022	Dec. 31, 2022 USD ($)	Aug. 31, 2020 USD ($)
Term loan										$ 2,151
Private Placement [Member]
Number of private placements | PrivatePlacement					2
SVB Term Loan [Member]
Total payoff amount of term loan	$ 6,500
Term loan	5,200							$ 0		2,151
Debt instrument accrued interest and prepayment premium	100
Debt instrument, principal amount				$ 14,000				$ 0		8,167
Interest-only payment period				24 months
Loan payment, number of consecutive equal monthly installments of principal including accrued interest | Installment				24
Debt instrument, maturity date								Feb. 01, 2024
Debt instrument, final payment fee amount	$ 1,200			$ 1,200				$ 1,200
Debt default additional interest charge				5%
Debt finance costs			$ 68								$ 57
Unamortized deferred charges										29
Financing costs paid											$ 27
Loan discounts-financing costs										3
Debt instrument, accrued final payment fee										1,040
Contingent interest rate increase								2%
Term loan discount interest										$ 24
Interest rate, floating						6.97%		10.25%	5.27%
SVB Term Loan [Member] | Term Loan Derivative Liability [Member]
Term loan derivative liability				$ 187
SVB Term Loan [Member] | Minimum [Member]
Interest rate, floating				4.25%
Long term debt percentage bearing adjusted floating interest rate				6.25%
SVB Term Loan [Member] | First Amendment
Debt instruments percentage of required to deposit unrestricted and unencumbered cash collateral			100%
Equity raise requirements, description								if the Company failed to receive positive data in its Phase 2b/3 PRISM trial or to raise by June 30, 2022 sufficient net proceeds from the sale of equity securities to finance its planned second Phase 3 clinical trial of Haduvio for prurigo nodularis and its ongoing operations (each a “Milestone Condition”), the Company would have been 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 have been used by SVB to prepay the SVB Term Loan at any time.
SVB Term Loan [Member] | First Amendment | Minimum [Member]
Debt instruments amount of required to maintain unrestricted and unencumbered cash			$ 20,000
Proceeds from the sale of equity securities							$ 15,000
SVB Term Loan [Member] | Third Amendment [Member]
Variable interest rate		3%
Proceeds from the sale of equity securities		$ 45,000
Debt finance costs								$ 21
SVB Term Loan [Member] | Third Amendment [Member] | Minimum [Member]
Interest rate, floating		4.25%
Long term debt percentage bearing adjusted floating interest rate		6.25%
SVB Term Loan [Member] | Prepayment Prior to First Anniversary of Effective Date [Member]
Prepayment premium percentage on principal amount				3%
SVB Term Loan [Member] | Prepayment After First Anniversary of Effective Date and Prior To Second Anniversary of Effective Date [Member]
Prepayment premium percentage on principal amount				2%
SVB Term Loan [Member] | Prepayment After Second Anniversary of the Effective Date and Prior to February 1, 2024 [Member]
Prepayment premium percentage on principal amount				1%
SVB Term Loan [Member] | Prime Rate [Member]
Variable interest rate				1%
SVB Term Loan [Member] | Prime Rate [Member] | Third Amendment [Member]
Variable interest rate		1%
SVB Term Loan [Member] | Adjusted Prime Rate [Member]
Variable interest rate				3%

Debt - Schedule of Outstanding

Debt - Schedule of Outstanding Borrowings under SVB Term Loan (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	May 09, 2023	Dec. 31, 2022	Aug. 13, 2020
Debt Instrument [Line Items]
Less current portion			$ 7,000
Term loan payable, non-current			2,151
SVB Term Loan [Member]
Debt Instrument [Line Items]
Principal outstanding under term loan	$ 0		8,167	$ 14,000
Term loan discount-interest			(24)
Term loan discount-unamortized deferred charges			(29)
Term loan discount-financing costs, net of accretion			(3)
Debt instrument, accrued final payment fee			1,040
Loans Payable, Noncurrent			9,151
Less current portion			7,000
Term loan payable, non-current	$ 0	$ 5,200	$ 2,151

Debt - Schedule of Components o

Debt - Schedule of Components of Interest Expense of Term Loan (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Interest expense	$ 3	$ 292	$ 387	$ 889
SVB Term Loan [Member]
Debt Instrument [Line Items]
Interest payments		170	202	470
Accrual of the final payment fee		89	150	309
Accretion and amortization of term loan discounts		33	30	110
Interest expense		$ 292	$ 382	$ 889

Stockholders' Equity - Shares R

Stockholders' Equity - Shares Reserved For Future Issuances (Detail) - shares	Sep. 30, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	53,656,248	84,187,372
Exercise of Outstanding Warrants And Pre-funded Warrants [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	45,330,707	48,330,707
LPC Purchase Agreement [Member]
Class Of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		30,000,000
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	6,549,024	4,553,202
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	1,208,274	701,232
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	568,243	602,231

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)

1 Months Ended

9 Months Ended

Jul. 23, 2023 shares

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

Jun. 30, 2023 USD ($)

May 31, 2022 USD ($)

Oct. 31, 2021 PrivatePlacement

Jun. 30, 2020 USD ($)

Sep. 30, 2023 USD ($) $ / shares shares

Sep. 30, 2022 USD ($)

Dec. 31, 2022 $ / shares

Stockholders Equity [Line Items]

Estimated commissions and allocated fees | $

$ 200,000

$ 195,000

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

$ 103,010,000

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

$ 0.001

$ 0.001

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 and private placements, net of issuance costs | $

$ 13,700,000

Number of private placements | PrivatePlacement

2

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

$ 1,100,000

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

Stockholders Equity [Line Items]

Sale of stock during the period

2,373,201

Warrants to purchase aggregate shares of common stock

4,746,402

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

Stockholders Equity [Line Items]

Sale of stock during the period

1,851,852

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

Stockholders Equity [Line Items]

Sale of stock during the period

4,580,526

Combined price of each shares | $ / shares

$ 1.90

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

Stockholders Equity [Line Items]

Exercise price per share of warrants | $ / shares

$ 0.001

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

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.899

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

$ 55,000,000

Exercise price per share of warrants | $ / shares

$ 0.001

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

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

1.62

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

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.62

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

$ 3,000,000

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

Stockholders Equity [Line Items]

Combined price of each shares | $ / shares

$ 1.619

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

$ 11,800,000

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

7,299,270

Exercise price per share of warrants | $ / shares

$ 1.37

Warrants expiration date

Apr. 05, 2025

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

1,851,852

Exercise price per share of warrants | $ / shares

$ 1.37

Warrants expiration date

Apr. 18, 2025

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

7,299,270

Warrants expiration date

Oct. 05, 2028

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

1,851,852

Warrants expiration date

Oct. 18, 2028

September 2022 Offering [Member] | Underwriting Agreement [Member]

Stockholders Equity [Line Items]

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

$ 58,100,000

Warrants expiration date

Sep. 27, 2022

September 2022 Offering [Member] | Common Stock [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

September 2022 Offering [Member] | Pre-funded Warrants [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

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

4,926,069

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

Stockholders Equity [Line Items]

Warrants to purchase aggregate shares of common stock

24,379,673

Maximum [Member] | September 2022 Offering [Member] | Pre-funded Warrants [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 | $

$ 75,000,000

$ 50,000,000

$ 12,000,000

$ 62,000,000

Sale of stock during the period

4,333,394

Proceeds from issuance of common stock | $

$ 12,700,000

Estimated commissions and allocated fees | $

$ 1,000,000

Proceeds from issuance of common stock, preferred stock, debt securities, units and or warrants | $

$ 200,000,000

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] | Maximum [Member] | Lincoln Park Capital Fund, LLC [Member]

Stockholders Equity [Line Items]

Sale of stock during the period

0

Shares agreed to be issued under equity line financing

15,000,000

Stockholders' Equity - Warrant

Stockholders' Equity - Warrant Activity Including Activity Related To Pre-funded Warrants (Detail)	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Pre-funded Warrants [Member]
Number of Other than Option Shares
Outstanding, Beginning	38,627,003
Exercised	(3,000,000)
Outstanding, Ending	35,627,003
Common Stock Warrant [Member]
Number of Other than Option Shares
Outstanding, Beginning	9,703,704
Outstanding, Ending	9,703,704
Warrant [Member]
Number of Other than Option Shares
Outstanding, Beginning	48,330,707
Exercised	(3,000,000)
Outstanding, Ending	45,330,707
Weighted Average Exercise Price
Outstanding, Beginning | $ / shares	$ 0.28
Exercised | $ / shares	0.001
Outstanding, Ending | $ / shares	$ 0.29

Stockholders' Equity (Stock-Bas

Stockholders' Equity (Stock-Based Awards) - Additional Information (Detail) - shares				1 Months Ended	9 Months Ended
	Jan. 01, 2023	Jan. 01, 2022	Jan. 01, 2020	Apr. 30, 2019	Sep. 30, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance					53,656,248	84,187,372
Share based compensation options to purchase no of common stock					5,315,543	4,450,283
Share based compensation options grants in the period					1,562,000
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 7,117,267 as of September 30, 2023, of which 1,801,724 shares remained available for grant under the 2019 Plan. Awards may be made under the 2019 Plan for up to such number of shares of the Company’s common stock as is equal to the sum of: i) 1,578,947 shares; plus ii) the number of shares (up to 1,157,894 shares) of the Company’s common stock subject to outstanding awards under the 2012 Plan that expire, terminate or are otherwise cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right; plus iii) an annual increase to be added on the first day of each fiscal year, beginning with 2020 and continuing through 2029, equal to the least of (a) 2,105,623 shares of common stock, (b) 4% of the number of outstanding shares of the Company’s common stock on such date, and (c) an amount determined by the Company’s board of directors.
Number of shares available for grant					1,801,724
Common stock, capital shares reserved for future issuance	2,105,623	1,140,232			1,578,947
Share based compensation grant period					10 years
Share based compensation vesting description					Options granted under the 2019 Plan and the 2012 Plan have a maximum term of ten years. Options granted to employees, officers and non-employees generally vest over four years based on varying vesting schedules that primarily include: 25% vesting on the first anniversary date of grant and the balance ratably over the next 36 months or vesting in equal monthly or quarterly installments over four years.
Share based compensation options to purchase no of common stock					4,747,300	3,848,052
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					7,117,267
2012 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation grant period					10 years
Share based compensation vesting description					Options granted under the 2019 Plan and the 2012 Plan have a maximum term of ten years. Options granted to employees, officers and non-employees generally vest over four years based on varying vesting schedules that primarily include: 25% vesting on the first anniversary date of grant and the balance ratably over the next 36 months or vesting in equal monthly or quarterly installments over four years.
Share based compensation options to purchase no of common stock					568,243	602,231
2012 Stock Incentive Plan [Member] | Other Equity-Based Award [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options grants in the period					0
2012 Stock Incentive Plan [Member] | Employees, Officers and Non-employee Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period					4 years
2012 Stock Incentive Plan [Member] | Employees, Officers and Non-employee Consultants [Member] | Vesting First Anniversary Date of Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting Percentage					25%
2012 Stock Incentive Plan [Member] | Director [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period					1 year
2012 Stock Incentive Plan [Member] | Director [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation vesting period					2 years
2012 Stock Incentive Plan [Member] | Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation options to purchase number of shares outstanding					1,157,894
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 1,208,274 as of September 30, 2023. 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, 2023 and January 1, 2022, 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 526,315 shares and 285,058 shares, equal to the 2019 ESPP determined maximum and 1% of the Company’s then-outstanding common stock, respectively
Total number of common shares authorized under the plan					1,208,274
Common stock, capital shares reserved for future issuance				155,106
2019 Employee Stock Purchase Plan [Member] | Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in additional number of shares to be issued	526,315	285,058		526,315
Percentage of number of common stock, shares outstanding	1%	1%		1%

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options, Activity (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2023
Number of Option Shares
Outstanding, Beginning	4,450,283
Granted	1,562,000
Forfeited	(318,075)
Expired	(234,876)
Exercised	(143,789)
Outstanding, Ending	5,315,543
Options exercisable	2,607,790
Options unvested	2,707,753
Weighted Average Exercise Price
Outstanding, Beginning	$ 3.26
Granted	2.62
Forfeited	1.77
Expired	3.23
Exercised	0.51
Outstanding, Ending	3.24
Options exercisable	4.32
Options unvested	$ 2.2

Stockholders' Equity - Stock-ba

Stockholders' Equity - Stock-based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 530	$ 569	$ 1,713	$ 1,826
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	319	371	1,056	1,195
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 211	$ 198	$ 657	$ 631

Net Loss per Share - Computatio

Net Loss per Share - Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Net loss	$ (7,698)	$ (8,266)	$ (21,244)	$ (23,647)
Weighted average common shares used in net loss per share attributable to common stockholders, basic	99,325,540	68,898,810	98,880,882	53,221,949
Weighted average common shares used in net loss per share attributable to common stockholders, diluted	99,325,540	68,898,810	98,880,882	53,221,949
Basic net loss per common share outstanding	$ (0.08)	$ (0.12)	$ (0.21)	$ (0.44)
Diluted net loss per common share outstanding	$ (0.08)	$ (0.12)	$ (0.21)	$ (0.44)

Net Loss per Share - Additional

Net Loss per Share - Additional Information (Details) - shares	Sep. 27, 2022	Apr. 06, 2022
April 2022 Private Placement [Member]
Earnings Per Share Basic [Line Items]
Pre-funded warrants to purchase of common stock	14,247,330	21,379,673

Net Loss per Share - Calculatio

Net Loss per Share - Calculation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	15,019,247	13,845,611
Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	5,315,543	4,141,907
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	9,703,704

Collaborative and Licensing A_2

Collaborative and Licensing Agreements - Additional Information (Detail) - Endo Pharmaceuticals Inc [Member] $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
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]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments to be paid	$ 0.3
Completion Of Stage Two [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments to be paid	$ 0.8