Achieve Life Sciences (ACHV) 10-Q 13 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 13, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Document Transition Report	false
Document Quarterly Report	true
Trading Symbol	ACHV
Entity Incorporation, State or Country Code	DE
Entity Registrant Name	Achieve Life Sciences, Inc.
Entity Central Index Key	0000949858
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity File Number	033-80623
Entity Tax Identification Number	95-4343413
Entity Address, Address Line One	1040 West Georgia Street
Entity Address, Address Line Two	Suite 1030
Entity Address, City or Town	Vancouver
Entity Address, State or Province	BC
Entity Address, Country	CA
Entity Address, Postal Zip Code	V6E 4H1
City Area Code	604
Local Phone Number	210-2217
Entity Common Stock, Shares Outstanding		34,341,303
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Other Address
Document Information [Line Items]
Entity Address, Address Line One	22722 29th Drive SE
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Bothell
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98021

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents [note 6]	$ 14,756	$ 15,546
Short-term investments [note 6]	46,557
Grant receivable [note 3]		111
Prepaid expenses and other assets	1,206	1,325
Total current assets	62,519	16,982
Right-of-use assets [note 9]	35	66
Other assets and restricted cash [note 6]	117	92
License agreement [note 4 and note 5]	1,086	1,197
Goodwill	1,034	1,034
Total assets	64,791	19,371
Current liabilities:
Accounts payable	550	618
Accrued liabilities other	617	351
Contingent consideration [note 5 and note 6]	637	528
Accrued clinical liabilities	1,708	280
Accrued compensation	1,349	2,311
Current portion of long-term obligations [note 9]	37	63
Current portion of convertible debt [note 6 and note 7]	8,804	16,662
Total current liabilities	13,702	20,813
Non-current portion of convertible debt [note 6 and note 7]	8,804
Long-term obligations [note 9]		6
Total liabilities	22,506	20,819
Commitments and contingencies [note 9]
Stockholders' equity:
Common stock, $0.001 par value, 150,000,000 shares authorized, 34,341,303 issued and outstanding at June 30, 2024 and 21,165,760 issued and outstanding at December 31, 2023	103	90
Additional paid-in capital	222,895	164,209
Accumulated deficit	(180,706)	(165,751)
Accumulated other comprehensive income	(7)	4
Total stockholders' equity	42,285	(1,448)
Total liabilities and stockholders' equity	64,791	19,371
Series A Convertible Preferred Stock [Member]
Stockholders' equity:
Convertible preferred stock, value
Series B Convertible Preferred Stock [Member]
Stockholders' equity:
Convertible preferred stock, value

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Preferred stock, par value	$ 0.001
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	34,341,303	21,165,760
Common stock, shares outstanding	34,341,303	21,165,760
Series A Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares designated	9,158	9,158
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Series B Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares designated	6,256	6,256
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Consolidated Statements of Loss

Consolidated Statements of Loss and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
EXPENSES
Research and development	$ 5,113	$ 4,585	$ 7,912	$ 10,119
General and administrative	3,318	3,129	6,501	6,173
Total operating expenses	8,431	7,714	14,413	16,292
OTHER INCOME (EXPENSE)
Interest income	833	193	1,201	355
Interest expense [note 7]	(804)	(712)	(1,617)	(1,285)
Change in fair value of contingent consideration [note 5 and note 6]	(57)		(109)
Other expense	(2)	(6)	(17)	(9)
Total other expense	(30)	(525)	(542)	(939)
Net loss	(8,461)	(8,239)	(14,955)	(17,231)
OTHER COMPREHENSIVE LOSS
Net unrealized loss on securities	(11)		(11)
Total other comprehensive loss	(11)		(11)
Comprehensive loss	$ (8,472)	$ (8,239)	$ (14,966)	$ (17,231)
Basic net loss per common share [note 8[d]]	$ (0.25)	$ (0.43)	$ (0.5)	$ (0.93)
Diluted net loss per common share [note 8[d]]	$ (0.25)	$ (0.43)	$ (0.5)	$ (0.93)
Weighted average shares used in computation of basic net loss per common share [note 8[d]]	34,318,709	19,048,627	29,683,422	18,486,322
Weighted average shares used in computation of diluted net loss per common share [note 8[d]]	34,318,709	19,048,627	29,683,422	18,486,322

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating Activities:
Net loss	$ (14,955)	$ (17,231)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization [note 4]	114	113
Stock-based compensation [note 8[c], note 8[e], note 8[f] and note 8[g]]	2,742	2,275
Accrued interest on SVB convertible debt [note 7]	624	606
Accretion of discount on modification of debt	322	107
Change in fair value of contingent consideration [note 5 and note 6]	109
Changes in operating assets and liabilities:
Grant receivable [note 3]	111	(245)
Prepaid expenses and other assets	61	1,517
Accounts payable	(68)	(1,299)
Accrued liabilities other	266	369
Accrued clinical liabilities	1,428	(689)
Accrued compensation	(962)	(444)
Lease obligation [note 9]	(1)	(58)
Net cash used in operating activities	(10,209)	(14,979)
Financing Activities:
Proceeds from exercise of warrants		227
Taxes paid related to net share settlement of equity awards	(114)	(220)
Net cash provided by financing activities	55,957	15,278
Investing Activities:
Purchase of investments	(46,568)
Net cash used in investing activities	(46,568)
Effect of exchange rate changes on cash		1
Net increase/(decrease) in cash, cash equivalents and restricted cash	(820)	300
Cash, cash equivalents and restricted cash at beginning of the period	15,596	24,821
Cash, cash equivalents and restricted cash at end of the period	14,776	25,121
November 2022 Private Placement [Member]
Financing Activities:
Financing costs relating to November 2022 private placement		(30)
May 2023 Private Placement [Member]
Financing Activities:
Proceeds from private placement, net of issuance costs		$ 15,301
February 2024 Private Placement [Member]
Financing Activities:
Proceeds from private placement, net of issuance costs	$ 56,071

Consolidated Statements of Stoc

Consolidated Statements of Stockholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	February 2024 Registered Direct Offering [Member]	November 2022 Private Placement [Member]	May 2023 Registered Direct Offering [Member]	Common Stock [Member]	Common Stock [Member] February 2024 Registered Direct Offering [Member]	Common Stock [Member] May 2023 Registered Direct Offering [Member]	Additional paid-in capital [Member]	Additional paid-in capital [Member] February 2024 Registered Direct Offering [Member]	Additional paid-in capital [Member] November 2022 Private Placement [Member]	Additional paid-in capital [Member] May 2023 Registered Direct Offering [Member]	Accumulated other comprehensive income (loss) [Member]	Accumulated deficit [Member]
Beginning Balance at Dec. 31, 2022	$ 8,303				$ 87			$ 144,148				$ 4	$ (135,936)
Beginning Balance, Shares at Dec. 31, 2022					17,897,029
Stock-based compensation expense	1,085							1,085
Shares issued on exercise of warrants	77							77
Shares issued on exercise of warrants, Shares					33,333
Financing costs			$ (30)							$ (30)
Net loss	(8,992)												(8,992)
Ending Balance at Mar. 31, 2023	443				$ 87			145,280				4	(144,928)
Ending Balance, Shares at Mar. 31, 2023					17,930,362
Beginning Balance at Dec. 31, 2022	$ 8,303				$ 87			144,148				4	(135,936)
Beginning Balance, Shares at Dec. 31, 2022					17,897,029
Restricted stock unit settlements, Shares	139,750
Net loss	$ (17,231)
Ending Balance at Jun. 30, 2023	9,699				$ 90			162,772				4	(153,167)
Ending Balance, Shares at Jun. 30, 2023					21,105,760
Beginning Balance at Mar. 31, 2023	443				$ 87			145,280				4	(144,928)
Beginning Balance, Shares at Mar. 31, 2023					17,930,362
Stock-based compensation expense	1,190							1,190
Shares issued on exercise of warrants	150							150
Shares issued on exercise of warrants, Shares					65,000
Shares issued				$ 15,301			$ 3				$ 15,298
Shares issued, Shares							3,000,000
SVB convertible debt refinancing discount	$ 1,074							1,074
Restricted stock unit settlements, Shares	139,750				139,750
Restricted stock unit settlements withheld and retired to treasury	$ (220)							(220)
Restricted stock unit settlements withheld and retired to treasury, Shares					(29,352)
Net loss	(8,239)												(8,239)
Ending Balance at Jun. 30, 2023	9,699				$ 90			162,772				4	(153,167)
Ending Balance, Shares at Jun. 30, 2023					21,105,760
Beginning Balance at Dec. 31, 2023	(1,448)				$ 90			164,209				4	(165,751)
Beginning Balance, Shares at Dec. 31, 2023					21,165,760
Stock-based compensation expense	1,288							1,288
Shares issued		$ 56,110				$ 13			$ 56,097
Shares issued, Shares						13,086,151
Net loss	(6,494)												(6,494)
Ending Balance at Mar. 31, 2024	49,456				$ 103			221,594				4	(172,245)
Ending Balance, Shares at Mar. 31, 2024					34,251,911
Beginning Balance at Dec. 31, 2023	$ (1,448)				$ 90			164,209				4	(165,751)
Beginning Balance, Shares at Dec. 31, 2023					21,165,760
Restricted stock unit settlements, Shares	113,125
Other comprehensive income	$ (11)
Net loss	(14,955)
Ending Balance at Jun. 30, 2024	42,285				$ 103			222,895				(7)	(180,706)
Ending Balance, Shares at Jun. 30, 2024					34,341,303
Beginning Balance at Mar. 31, 2024	49,456				$ 103			221,594				4	(172,245)
Beginning Balance, Shares at Mar. 31, 2024					34,251,911
Stock-based compensation expense	$ 1,454							1,454
Financing costs		$ (39)							$ (39)
Restricted stock unit settlements, Shares	113,125				113,125
Restricted stock unit settlements withheld and retired to treasury	$ (114)							(114)
Restricted stock unit settlements withheld and retired to treasury, Shares					(23,733)
Other comprehensive income	(11)											(11)
Net loss	(8,461)												(8,461)
Ending Balance at Jun. 30, 2024	$ 42,285				$ 103			$ 222,895				$ (7)	$ (180,706)
Ending Balance, Shares at Jun. 30, 2024					34,341,303

Nature of Business, Basis of Pr

Nature of Business, Basis of Presentation and Liquidity Risk	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Nature of Business, Basis of Presentation and Liquidity Risk	1. NATURE OF BUSINESS, BASIS OF PRESENTATION AND LIQUIDITY RISK Achieve Life Sciences, Inc. (referred to as “Achieve,” “we,” “us,” or “our”) is a clinical-stage pharmaceutical company committed to the global development and commercialization of cytisinicline for smoking cessation and nicotine addiction. We were incorporated in the state of Delaware, and operate out of Seattle, Washington and Vancouver, British Columbia. The unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States, or U.S. GAAP, for interim financial information and with the instructions to Form 10-Q. Accordingly, they do not include all of the information and footnotes required to be presented for complete financial statements. The accompanying unaudited consolidated financial statements reflect all adjustments (consisting only of normal recurring items) which are, in the opinion of management, necessary for a fair presentation of the results for the interim periods presented. The accompanying consolidated Balance Sheet at December 31, 2023 has been derived from the audited consolidated financial statements included in our Annual Report on Form 10-K for the year then ended. The unaudited consolidated financial statements and related disclosures have been prepared with the assumption that users of the interim financial information have read or have access to the audited consolidated financial statements for the preceding fiscal year. Accordingly, these financial statements should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2023 and filed with the U.S. Securities and Exchange Commission, or the SEC, on March 28, 2024. The consolidated financial statements include the accounts of Achieve and our wholly owned subsidiaries, Achieve Life Sciences Technologies Inc., Achieve Life Science, Inc., Extab Corporation, and Achieve Pharma UK Limited. All intercompany balances and transactions have been eliminated. Liquidity We have historically experienced recurring losses from operations and have incurred an accumulated deficit of $ 180.7 million through June 30, 2024. As of June 30, 2024, we had cash, cash equivalents and short-term investments of $ 61.3 million and a positive working capital balance of $ 48.8 million. For the six months ended June 30, 2024, we incurred a net loss of $ 15.0 million and net cash used in operating activities was $ 10.2 million. We have historically financed our operations through equity and debt financings. While we believe that we will be able to settle our commitments and liabilities in the normal course of business as they fall due during the next 12 months, as a development-stage company with no current sources of revenue, we are dependent on our ability to raise funds (through public or private securities offerings, debt financings, government funding or grants, or other sources, which may include licensing, collaborations or other strategic transactions or arrangements) to support the ongoing advancement of our clinical trials and corporate activities.

Accounting Policies

Accounting Policies	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Accounting Policies	2. ACCOUNTING POLICIES The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and related disclosures. We have discussed those estimates that we believe are critical and require the use of complex judgment in their application in our audited financial statements for the year ended December 31, 2023 in our Annual Report on Form 10-K filed with the SEC, on March 28, 2024. Since December 31, 2023, there have been no material changes to our critical accounting policies or the methodologies or assumptions we apply under them other than the ones noted below under "Significant Accounting Policies" . Significant Accounting Policies Short-Term Investments Short-term investments consist of financial instruments purchased with an original maturity of greater than three months and less than one year. We consider our short-term investments as available-for-sale and carry them at fair value, with unrealized gains and losses, if any, reported as accumulated other comprehensive income or loss, which is a separate component of stockholders’ equity. Realized gains and losses on the sale or impairment, if any, of these securities, are recognized in net income or loss. The cost of investments sold is based on the specific identification method. Fair value of financial instruments The fair value of our marketable securities is based on quoted market prices and trade data for comparable securities.

Government Grant

Government Grant	6 Months Ended
	Jun. 30, 2024
Receivables [Abstract]
Government Grant	3. GOVERNMENT GRANT In July 2021, we announced that we were awarded a grant from the National Institute on Drug Abuse, or NIDA, of the National Institutes of Health, or NIH, to evaluate the use of cytisinicline as a treatment for cessation of nicotine e-cigarette use. This initial grant award, in the amount of $ 0.3 million, commenced on August 1, 2021, and was utilized to complete critical regulatory and clinical operational activities, such as protocol finalization, clinical trial site identification, drug packaging, and submission of a new Investigational New Drug Application, or IND, to the U.S. Food and Drug Administration, or FDA, for investigating cytisinicline in nicotine e-cigarette users. In November 2021, we announced that the FDA had completed their review and accepted the Investigational New Drug Application to investigate cytisinicline as a cessation treatment in this population. In June 2022, following NIH review of completed milestones, we announced that we were awarded the next grant funding from the NIDA in the amount of approximately $ 2.5 million, which we have used to conduct the ORCA-V1 Phase 2 clinical trial. In June 2022, we announced the initiation of the ORCA-V1 Phase 2 clinical trial. ORCA-V1 will evaluate the efficacy and safety of 3 mg cytisinicline dosed three times daily compared to placebo in approximately 160 adult e-cigarette users at five clinical trial locations in the United States. Participants were randomized to receive cytisinicline or placebo for 12 weeks in combination with standard cessation behavioral support. The NIDA/NIH grant for ORCA-V1 was fully utilized as of the first quarter of 2024 and we have received the full amount of approximately $ 2.5 million in reimbursements from NIDA/NIH. We do not expect to receive any further reimbursements from this grant. For the six months ended June 30, 2024 , we incurred $ 16,000 in qualifying research and development, or R&D, expenditures, all of which were incurred in the first quarter of 2024, under the NIDA/NIH grant, which has been recorded as a reduction in R&D expense. The grant award covered approximately half of the total ORCA-V1 clinical study costs. The Primary Investigators for the grant were our Chief Medical Officer, Dr. Cindy Jacobs, and Dr. Nancy Rigotti, Professor of Medicine at Harvard Medical School and Director, Tobacco Research and Treatment Center, Massachusetts General Hospital.

Intangibles

Intangibles	6 Months Ended
	Jun. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangibles	4. INTANGIBLES All of our intangible assets are subject to amortization and are amortized using the straight-line method over their estimated useful life. We acquired license and supply agreements in relation to cytisinicline upon the acquisition of Extab Corporation, or Extab, on May 18, 2015. The agreements were determined to have a fair value of $ 3.1 million with an estimated useful life of 14 years. The components of intangible assets were as follows: June 30, 2024 December 31, 2023 Gross Carrying Accumulated Net Carrying Gross Carrying Accumulated Net Carrying Value Amortization Value Value Amortization Value License Agreements $ 3,117 $ ( 2,031 ) $ 1,086 $ 3,117 $ ( 1,920 ) $ 1,197 For the three and six months ended June 30, 2024 , we recorded license agreement amortization expense of $ 0.1 million and $ 0.1 million, respectively. For the three and six months ended June 30, 2023 , we recorded license agreement amortization expense of $ 0.1 million and $ 0.1 million, respectively. The following table outlines the estimated future amortization expense related to intangible assets held as of June 30, 2024 : Year Ending December 31, 2024 112 2025 223 2026 223 2027 223 Thereafter 305 Total $ 1,086 We evaluate the carrying amount of intangible assets periodically by taking into account events or circumstances that may warrant revised estimates of useful life or that indicate the asset may be impaired. We conducted an analysis of potential impairment indicators for long lived assets, including the license and supply agreements for the active pharmaceutical ingredient cytisinicline, and concluded that there were no indicators of impairment identified as of June 30, 2024 .

License Agreements

License Agreements	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	5. LICENSE AGREEMENTS Sopharma License and Supply Agreements We are party to a license agreement, or the Sopharma License Agreement, and a supply agreement, or the Sopharma Supply Agreement, with Sopharma, AD, or Sopharma. Pursuant to the Sopharma License Agreement, we were granted access to all available manufacturing, efficacy and safety data related to cytisinicline, as well as a granted patent in several European countries related to new oral dosage forms of cytisinicline providing enhanced stability. Additional rights granted under the Sopharma License Agreement include the exclusive use of, and the right to sublicense, certain cytisinicline trademarks in all territories described in the Sopharma License Agreement. Under the Sopharma License Agreement, we agreed to pay a nonrefundable license fee. In addition, we agreed to make certain royalty payments equal to a mid-single digit percentage of all net sales of cytisinicline products in our territory during the term of the Sopharma License Agreement, including those sold by a third party pursuant to any sublicense which may be granted by us. To date, any amounts paid to Sopharma pursuant to the Sopharma License Agreement have been immaterial. Share Purchase Agreement On May 14, 2015, we entered into a Share Purchase Agreement with Sopharma to acquire 75 % of the outstanding shares of Extab for $ 2.0 million in cash and $ 2.0 million in a deferred payment, contingent on regulatory approval of cytisinicline by the FDA or the European Medicines Agency. The fair value of the contingent consideration on the acquisition date was nil. The contingent consideration liability is measured at fair value in our financial statements. As of June 30, 2024, the fair value of the contingent consideration was estimated to be $ 0.6 million. We recognized a loss of $ 0.1 million and $ 0.1 million for the three and six months ended June 30, 2024, respectively.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. FAIR VALUE MEASUREMENTS Assets and liabilities recorded at fair value in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair value. For certain of our financial instruments including amounts receivable and accounts payable the carrying values approximate fair value due to their short-term nature. ASC 820 “Fair Value Measurements and Disclosures” specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. In accordance with ASC 820, these inputs are summarized in the three broad levels listed below: • Level 1 – Quoted prices in active markets for identical securities. • Level 2 – Other significant inputs that are observable through corroboration with market data (including quoted prices in active markets for similar securities). • Level 3 – Significant unobservable input that reflects management’s best estimate of what market participants would use in pricing the asset or liability. As quoted prices in active markets are not readily available for certain financial instruments, we obtain estimates for the fair value of financial instruments through third-party pricing service providers. In determining the appropriate levels, we performed a detailed analysis of the assets and liabilities that are subject to ASC 820. We invest our excess cash in accordance with investment guidelines that limit the credit exposure to any one financial institution other than securities issued by the U.S. Government. These securities are not collateralized and mature within one year . A description of the valuation techniques applied to our financial instruments measured at fair value on a recurring basis follows. Financial Instruments The following table presents information about our assets and liabilities that are measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques we utilized to determine such fair value (in thousands): June 30, 2024 Level 1 Level 2 Level 3 Total Assets Money market securities (cash equivalents) $ 14,466 $ — $ — $ 14,466 Restricted cash 20 — — 20 US government securities — 27,093 — 27,093 Corporate bonds — 18,478 — 18,478 Commercial paper — 986 — 986 Total assets $ 14,486 $ 46,557 $ — $ 61,043 Liabilities Convertible debt $ — 17,585 $ — $ 17,585 Contingent consideration — — 637 637 Total liabilities $ — $ 17,585 $ 637 $ 18,222 Money Market Securities Money market securities are classified within Level 1 of the fair value hierarchy and are valued based on quoted prices in active markets for identical securities. Cash equivalents consist of the following (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated June 30, 2024 Cost Gains Losses Fair Value Money market securities $ 14,466 $ — $ — $ 14,466 Total cash equivalents $ 14,466 $ — $ — $ 14,466 Money market securities (restricted cash) $ 20 $ — $ — $ 20 Total restricted cash $ 20 $ — $ — $ 20 We only invest in A (or equivalent) rated securities. All securities included in cash and cash equivalents had maturities of 90 days or less at the time of purchase. Corporate and Other Debt Corporate Bonds and Commercial Paper The fair value of corporate bonds and commercial paper is estimated using recently executed transactions, market price quotations (where observable), bond spreads or credit default swap spreads adjusted for any basis difference between cash and derivative instruments. The spread data used are for the same maturity as the bond. If the spread data does not reference the issuer, then data that reference a comparable issuer are used. When observable price quotations are not available, fair value is determined based on cash flow models with yield curves, bond or single name credit default swap spreads and recovery rates based on collateral values as significant inputs. Corporate bonds and commercial paper are generally categorized in Level 2 of the fair value hierarchy; in instances where prices, spreads or any of the other aforementioned key inputs are unobservable, they are categorized in Level 3 of the hierarchy. Gross Gross Amortized Unrealized Unrealized Estimated June 30, 2024 Cost Gains Losses Fair Value US government securities $ 27,100 $ — $ ( 7 ) $ 27,093 Corporate bonds 18,482 — ( 4 ) 18,478 Commercial paper 986 — — 986 Total short term investments $ 46,568 $ — $ ( 11 ) $ 46,557 Concentration of Cash and Cash Equivalents Risk We place our cash in a custodial account and in commercial checking and sweep accounts with various financial institutions. As of June 30, 2024 , approximately $ 58.8 million in cash equivalents and short-term investments is held in a custodial account with U.S. Bank, for which SVB Asset Management is the advisor; and approximately $ 0.1 million of our cash and $ 1.7 million of our cash equivalents is held in a single financial institution, SVB, as required by the covenants of the Debt Agreement (Note 7 – Convertible Debt). Our commercial bank balances exceed federal insurance limits. We have not experienced any losses in our cash and cash equivalents for the six months ended June 30, 2024 and 2023. Fair Value of Debt December 2021 Convertible Debt The principal amount, carrying value and related estimated fair value of our convertible debt reported in the consolidated balance sheets as of June 30, 2024 and December 31, 2023 was as follows (in thousands). The aggregate fair value of the principal amount of the convertible debt is a Level 2 fair value measurement. June 30, 2024 December 31, 2023 Principal Carrying Fair Principal Carrying Fair Amount Value Value Amount Value Value December 2021 Convertible Debt $ 15,000 $ 17,608 $ 17,585 $ 15,000 $ 16,662 $ 16,652 Fair Value of Sopharma Share Purchase Agreement Contingent Consideration We determine the fair value of the contingent consideration using a probability based discounted cash flow model whereby we forecast the timing of the cash flow of the related future payment based on cytisinicline’s current clinical development phase and the remaining requirements for regulatory approval. We then discount the expected payment amount to calculate the present value and then apply a probability of success in obtaining regulatory approval as of the valuation date. We evaluate the underlying projection used in determining the fair value each period and make updates as necessary. The significant assumptions we use to value the contingent consideration are the forecasted timing of the future payment, the risk-adjusted discount rate and the probability of success which are all considered significant unobservable inputs, and as such, the liability is classified as a Level 3 measurement. The risk-adjusted discount rate is adjusted for credit risk. An increase in the discount rate and decrease in the probability of success will result in a decrease in the fair value of the contingent consideration. Conversely, a decrease in the discount rate and increase in the probability of success will result in an increase in the fair value of the contingent consideration. At June 30, 2024 the risk adjusted discount rate was 38.0 % and the probability of success was 67.2 %. Adjustments to the fair value of the contingent liabilities, other than payments, are recorded as a gain or loss in the Consolidated Statements of Loss and Comprehensive Loss . The following table presents the changes in fair value of our total Level 3 financial liabilities for the six months ended June 30, 2024: Balance at Change in Balance at (in thousands) December 31, 2023 Fair Value June 30, 2024 Contingent consideration $ 528 $ 109 $ 637

Convertible Debt

Convertible Debt	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Convertible Debt	7. CONVERTIBLE DEBT Convertible Debt On December 22, 2021, we entered into a $ 25.0 million contingent convertible debt agreement, or Original Debt Agreement, with Silicon Valley Bank, or SVB, and SVB Innovation Credit Fund VIII, L.P., or, together with SVB, the Lenders. As part of the Original Debt Agreement, the Lenders funded $ 15.0 million in the form of convertible indebtedness, or Convertible Debt, at closing. On April 26, 2022, we entered into (i) a loan and security agreement, or Loan Agreement, with SVB for the remaining $ 10.0 million remaining in the Original Debt Agreement, pursuant to which SVB provided a commitment to extend term loans having an aggregate original principal amount of up to $ 10.0 million, or Term Loans, and (ii) a first amendment to the Original Debt Agreement, or the Amendment, and as amended by the Amendment, the Debt Agreement. The availability of Term Loans under the Loan Agreement expired on April 30, 2023 , with no amounts drawn under the facility. On May 15, 2023, we entered into a contingent convertible debt agreement, or Debt Agreement, with the Lenders, pursuant to which the Lenders provided term loans having an aggregate original principal amount of $ 16.6 million, or the Convertible Term Loan. The Convertible Debt under the Original Debt Agreement was refinanced as the Convertible Term Loan pursuant to the Debt Agreement. Our obligations under the Loan Agreement, Original Debt Agreement and Convertible Debt were satisfied in full and the Loan Agreement, Original Debt Agreement and Convertible Debt were terminated in connection with the entrance into the Debt Agreement and Convertible Term Loan. Interest is calculated on the outstanding principal amount of the Convertible Term Loan at the aggregate of (a) a floating rate per annum equal to the greater of (i) 2.25 % and (ii) the prime rate minus 1.0 %, which interest shall be payable in cash monthly in arrears, and (b) 7.0 % per annum, compounded monthly, which shall be payable on the earlier to occur of the maturity date and the date that the Convertible Term Loan is converted into our common stock. The Debt Agreement contains customary affirmative and restrictive covenants, including covenants regarding the incurrence of additional indebtedness or liens, investments, transactions with affiliates, delivery of financial statements, payment of taxes, maintenance of insurance, dispositions of property, mergers or acquisitions, among other customary covenants. We are also restricted from paying dividends or making other distributions or payments on our capital stock, subject to limited exceptions. The Debt Agreement also includes customary representations and warranties, events of default and termination provisions. The Lenders may not engage in any short sales of, or other hedging transactions in, our common stock while any amounts are outstanding under the Debt Agreement. Our obligations under the Debt Agreement are secured by substantially all of our assets, other than intellectual property. Under ASU 2020-06 for the Original Debt Agreement, the embedded conversion feature was not required to be bifurcated and recognized separately, as a result the convertible debt including the conversion feature has been recognized as a single unit of debt. The debt issuance costs related to Convertible Debt under the Original Debt Agreement have been recognized against the single unit of debt and will be amortized into interest expense over the term of the Convertible Term Loan. The debt refinancing in May 2023 was recognized as a debt modification under ASU 470-50 and the associated third-party issuance costs were expensed. As of June 30, 2024 and December 31, 2023, the Convertible Term Loan balance, including the Convertible Debt balance, was comprised of the following: June 30, December 31, 2024 2023 Convertible Term Loan Information Principal $ 15,000 $ 15,000 Transaction Costs ( 5 ) ( 5 ) Accrued paid-in-kind interest 2,935 2,311 Discount on modification of debt ( 1,074 ) ( 1,074 ) Accretion of discount on modification of debt 752 430 17,608 16,662 On July 25, 2024, we entered into a contingent convertible debt agreement, or New Debt Agreement , with SVB, a division of First-Citizens Bank & Trust Company, or FCB, in its capacity as administrative agent and collateral agent, and FCB, as a lender, or Lender, pursuant to which the Lender provided term loans having an aggregate original principal amount of $ 10.0 million, with additional term loans of up to $ 10.0 million available upon the occurrence of certain events as provided for in the New Debt Agreement. The New Debt Agreement refinanced our Debt Agreement entered into on May 15, 2023 . Our obligations under the Debt Agreement and Convertible Term Loan were satisfied in full and the Debt Agreement and Convertible Term Loan were terminated in connection with the entrance into the New Debt Agreement and New Convertible Term Loan (see Note 10 “Subsequent Events”).

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Common Stock	8. COMMON STOCK [a] Authorized 150,000,000 authorized common shares, par value of $ 0.001 , and 5,000,000 preferred shares, par value of $ 0.001 . [b] Issued and outstanding shares At-the-Market Sales Agreement On December 21, 2021, we entered into an At-the-Market Offering Sales Agreement, or ATM, with Virtu Americas, LLC, as sales agent. The ATM was terminated on February 29, 2024, and no further sales of our common stock will be made pursuant to the ATM. Since entry into the ATM, through the date of termination of the ATM, we offered and sold an aggregate of 200,000 shares of our common stock. These aggregate sales resulted in gross proceeds to us of approximately $ 1.5 million. During the three and six months ended June 30, 2024, we did no t sell any shares of our common stock pursuant to the ATM. May 2023 Registered Direct Offering In May 2023, we entered into a securities purchase agreement with certain purchasers, pursuant to which we sold 3,000,000 shares of common stock at a price of $ 5.50 per share in a registered direct offering. The offering of the shares was made pursuant to our shelf registration statement on Form S-3 including the prospectus dated January 5, 2022 contained therein, and the prospectus supplement dated May 25, 2023. We received approximately $ 15.3 million in net proceeds from the registered direct offering after deducting placement agent fees and offering expenses. February 2024 Registered Direct Offering and Concurrent Private Placement In February 2024, we entered into a securities purchase agreement with certain purchasers, pursuant to which we sold 13,086,151 shares of common stock at a price of $ 4.585 per share in a registered direct offering. The offering of the shares was made pursuant to our shelf registration statement on Form S-3, including the prospectus dated January 5, 2022 contained therein, and the prospectus supplement dated February 28, 2024. In a concurrent private placement, we issued unregistered warrants to purchase up to 13,086,151 shares of common stock at an exercise price of $ 4.906 per share (provided, however, that the purchaser may elect to exercise the warrants for pre-funded warrants in lieu of shares of common stock at an exercise price of $ 4.906 , minus $ 0.001 , the exercise price of each pre-funded warrant). These warrants are immediately exercisable for shares of common stock or pre-funded warrants in lieu thereof, and will expire on the earlier of (i) three and one-half years following the date of issuance and (ii) 30 days following our public disclosure of the acceptance of an NDA for cytisinicline by the FDA in a Day 74 Letter or equivalent correspondence. The shares of common stock issuable upon exercise of the warrants (or pre-funded warrants, as applicable) were subsequently registered pursuant to our registration statement on Form S-3, which was declared effective on May 6, 2024. The registered direct offering raised total gross proceeds of approximately $ 60.0 million, and after deducting approximately $ 3.9 million in placement agent fees and offering expenses, we received net proceeds of approximately $ 56.1 million. Equity Award Issuances and Settlements During the three and six months ended June 30, 2024 , we did no t issue any shares of common stock to satisfy stock option exercises, and we issued 113,125 shares of common stock during each of the three and six months ended June 30, 2024 to satisfy restricted stock unit settlements. During the three and six months ended June 30, 2023, we did no t issue any shares of common stock to satisfy stock option exercises, and issued 139,750 shares of our common stock during each of the three and six months ended June 30, 2023 to satisfy restricted stock unit settlements. [c] Stock options 2023 Non-Employee Director Equity Incentive Plan As of June 30, 2024, we had reserved, pursuant to the 2023 Non-Employee Director Equity Incentive Plan, or the 2023 Non-Employee Director Plan, 300,000 shares of common stock for issuance upon exercise of stock options by non-employee directors, of which 290,250 shares were reserved for options currently outstanding and 9,750 shares were available for future equity grants. Under the 2023 Non-Employee Director Plan, we may grant options to purchase shares of our common stock or restricted stock units to our non-employee directors. The exercise price of the options is determined by our board of directors, or Board, but will be at least equal to the fair value of the shares of common stock at the grant date. The options vest in accordance with terms as determined by our Board, typically over one to three years . The expiration date for each option is set by our Board with a maximum expiration date of ten years from the date of grant. In addition, the 2023 Non-Employee Director Plan allows for accelerated vesting of outstanding equity awards in the event of a change in control. 2018 Equity Incentive Plan As of June 30, 2024, we had reserved, pursuant to the 2018 Equity Incentive Plan, or the 2018 Plan, 2,667,416 shares of common stock for issuance upon exercise of stock options and settlement of restricted stock units by employees, directors, officers and consultants of ours, of which 1,489,905 were reserved for options currently outstanding, 1,115,750 for restricted stock units currently outstanding, and 61,761 were available for future equity grants. Under the 2018 Plan, we may grant options to purchase common shares or restricted stock units to our employees, directors, officers and consultants. The exercise price of the options is determined by our Board, but will be at least equal to the fair value of the shares of common stock at the grant date. The options vest in accordance with terms as determined by our Board, typically over three to four years for options issued to employees and consultants, and over one to three years for members of our Board. The expiry date for each option is set by our Board with a maximum expiration date of ten years from the date of grant. In addition, the 2018 Plan allows for accelerated vesting of outstanding equity awards in the event of a change in control. The terms for accelerated vesting, in the event of a change in control, is determined at our discretion and defined under the employment agreements for our officers and certain of our employees. New Employee Inducement Grants We grant stock options as a material inducement to new employees for entering into employment agreements with us in accordance with Nasdaq Listing Rule 5635(c)(4). The stock options approved under the inducement grants are issued pursuant to a stock option agreement on terms substantially similar to those described in our 2018 Plan. The exercise price of the options is determined by our board of directors but will be at least equal to the fair value of the common shares at the grant date. The options vest in accordance with terms as determined by our Board. The expiration date for each option is set by our Board with a maximum expiration date of ten years from the date of grant. For the three and six months ended June 30, 2024 , we did no t grant any inducement stock options to new employees. As of June 30, 2024, 135,000 stock options granted as new employee inducement grants were outstanding. 2017 Equity Incentive Plan As of June 30, 2024 , we had reserved, pursuant to the 2017 Equity Incentive Plan, or the 2017 Plan, 13,156 shares of common stock for issuance upon exercise of currently outstanding stock options by employees, directors and officers of ours. Upon the effectiveness of our 2018 Plan, we ceased granting equity awards under our 2017 Plan. Under the 2017 Plan, we granted options to purchase shares of common stock or restricted stock units to our employees, directors, officers and consultants. The exercise price of the options was determined by our Board but was at least equal to the fair value of the shares of common stock at the grant date. The options vest in accordance with terms as determined by our Board, typically over three to four years for options issued to employees and consultants, and over one to three years for members of our Board. The expiration date for each option was set by our Board with a maximum expiration date of ten years from the date of grant. In addition, the 2017 Plan allows for accelerated vesting of outstanding equity awards in the event of a change in control. The terms for accelerated vesting, in the event of a change in control, is determined at our discretion and defined under the employment agreements for our officers and certain of our employees. 2010 Performance Incentive Plan As of June 30, 2024 , we had reserved, pursuant to the 2010 Performance Incentive Plan, or the 2010 Plan, 128 shares of common stock for issuance upon exercise of currently outstanding stock options by employees, directors and officers of ours. Upon the effectiveness of our 2017 Plan, we ceased granting equity awards under our 2010 Plan. Under the 2010 Plan we granted options to purchase shares of common stock and restricted stock units to our employees, directors, officers and consultants. The exercise price of the options was determined by our board of directors and was at least equal to the fair value of the shares of common stock at the grant date. The options vest in accordance with terms as determined by our Board, typically over three to four years for options issued to employees and consultants, and over one to three years for members of our Board. The expiration date for each option is set by our Board with a maximum expiration date of ten years from the date of grant. In addition, the 2010 Plan allows for accelerated vesting of outstanding equity awards in the event of a change in control. The terms for accelerated vesting, in the event of a change in control, is determined at our discretion and defined under the employment agreements for our officers and certain of our employees. Stock Option Summary We grant stock options that vest over time in accordance with terms as determined by our Board, which are typically four years for employee and consultant grants and one to three years for Board option grants. We also grant stock option awards that vest in conjunction with certain performance conditions to executive officers, employees and consultants. At each reporting date, we are required to evaluate whether achievement of the performance conditions is probable. Compensation expense is recorded over the appropriate service period based upon our assessment of accomplishing each performance condition. The expiration date for each option is set by our Board, which is typically seven to ten years . The exercise price of the options is determined by our Board. Stock option transactions and the number of stock options outstanding are summarized below: Number of Weighted Optioned Average Common Exercise Shares Price Balance, December 31, 2023 1,461,980 $ 12.12 Granted 466,500 4.55 Expired ( 41 ) 24,184.44 Balance, June 30, 2024 1,928,439 $ 9.78 The fair value of each stock award for employees and directors is estimated on the grant date and for consultants at each reporting period, using the Black-Scholes option-pricing model based on the weighted-average assumptions noted in the following table: Six Months Ended June 30, 2024 2023 Risk-free interest rates 4.00 % 3.60 % Expected dividend yield 0 % 0 % Expected life 5.65 years 5.75 years Expected volatility 90.15 % 115.19 % Forfeiture rate 0.00 % 0.00 % The expected life was calculated based on the simplified method as permitted by the SEC’s Staff Accounting Bulletin 110, Share-Based Payment . We consider the use of the simplified method appropriate because of the lack of sufficient historical exercise data following the 2017 Merger Agreement between Achieve Life Sciences, Inc. and OncoGenex Pharmaceuticals. The computation of expected volatility was calculated based on the historical volatility of the shares of our common stock. The risk-free interest rate is based on a U.S. Treasury instrument whose term is consistent with the expected life of the stock options. In addition to the assumptions above, as required under ASC 718, management made an estimate of expected forfeitures and is recognizing compensation costs only for those equity awards expected to vest. Forfeiture rates are estimated using historical actual forfeiture rates. These rates are adjusted on a quarterly basis and any change in compensation expense is recognized in the period of the change. We have never paid or declared cash dividends on our common stock and do not expect to pay cash dividends in the foreseeable future. The results for the periods set forth below included share-based compensation expense for stock options, restricted stock units and employee share purchase plan compensation expenses in the following expense categories of the consolidated statements of loss (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Research and development $ 486 $ 403 $ 899 $ 786 General and administrative $ 968 786 1,843 1,489 Total stock-based compensation $ 1,454 $ 1,189 $ 2,742 $ 2,275 As of June 30, 2024 , the total unrecognized compensation expense related to stock options granted was $ 3.5 million, which is expected to be recognized as expense over a period of approximately 1.62 years from June 30, 2024. [d] Loss Per Share For the six months ended June 30, 2024 , a total of 21,219,368 shares, consisting of warrants to purchase 18,175,179 shares, options exercisable for 1,928,439 shares and 1,115,750 restricted stock units, have not been included in the loss per share computation, as their effect on diluted per share amounts would have been anti-dilutive. For the same period in 2023 , a total of 7,090,100 shares underlying options, restricted stock units and warrants have not been included in the loss per share computation. Additionally, the outstanding Convertible Term Loan is included in the calculation of diluted per share amounts only if its inclusion is dilutive for periods during which the notes were outstanding. As of June 30, 2024, the outstanding Convertible Term Loan was not included in the calculation of diluted per share amounts as its effect would have been anti-dilutive. [e] Restricted Stock Unit Awards We grant restricted stock unit awards that generally vest and are expensed over a four-year period. We also grant restricted stock unit awards that vest in conjunction with certain performance conditions to certain executive officers, key employees and consultants. At each reporting date, we are required to evaluate whether achievement of the performance conditions is probable. Compensation expense is recorded over the appropriate service period based upon our assessment of accomplishing each performance condition. For the three and six months ended June 30, 2024 , we recorded a compensation expense of $ 0.6 million and $ 1.1 million, respectively, related to these awards, compared to $ 0.5 million and $ 1.0 million for the three and six months ended June 30, 2023. The following table summarizes our restricted stock unit award activity during the six months ended June 30, 2024: Weighted Number Average of Grant Date Shares Fair Value Balance, December 31, 2023 507,875 $ 5.65 Granted 721,000 4.55 Released ( 113,125 ) 8.26 Balance, June 30, 2024 1,115,750 $ 4.67 As of June 30, 2024, we had approximately $ 2.5 million in total unrecognized compensation expense related to our restricted stock unit awards that is to be recognized over a weighted-average period of approximately 1.25 years. [f] Non-employee options and restricted stock units We recognize non-employee stock-based compensation expense over the period of expected service by the non-employee. As the service is performed, we are required to update our valuation assumptions, re-measure unvested options and restricted stock units and record the stock-based compensation using the valuation as of the vesting date. This differs from the accounting for employee awards where the fair value is determined at the grant date and is not subsequently adjusted. This re-measurement may result in higher or lower stock-based compensation expense in the Consolidated Statements of Loss and Comprehensive Loss. As such, changes in the market price of our stock could materially change the value of an option or restricted stock unit and the resulting stock-based compensation expense. [g] Employee Share Purchase Plan Our Board and stockholders approved the 2017 Employee Stock Purchase Plan, or ESPP, in August 2017. Contributions are made by eligible employees, subject to certain limits defined in the ESPP. The number of shares available for future purchases under the ESPP is 556,270 shares. All shares purchased under the ESPP are new share issuances. For the three and six months ended June 30, 2024 , we recorded a compensation expense of $ 0.1 million and $ 0.1 million, respectively, related to the current ESPP offering period. For the three and six months ended June 30, 2023, no compensation expense was recognized related to our ESPP as we did not have an active offering period. During the three months ended June 30, 2024 and 2023 , no shares were purchased under the ESPP. [h] Common Stock Warrants The following is a summary of outstanding warrants to purchase common stock as of June 30, 2024: Total Outstanding Exercise and price per Exercisable Share Expiration Date (1) Warrants issued in May 2019 financing 60,000 $ 90.000 May 2025 (2) Warrants issued in December 2019 financing 510,924 $ 2.310 December 2024 (3) Warrants issued in April 2020 financing 182,461 $ 7.240 April 2025 (4) Warrants issued in April 2020 financing 24,375 $ 7.320 April 2025 (5) Warrants issued in April 2020 financing 25,270 $ 7.590 April 2025 (6) Pre-Funded warrants issued in August 2020 financing 142,857 $ 0.001 * (7) Warrants issued in December 2020 financing 50,000 $ 8.750 December 2025 (8) Warrants issued in November 2022 financing 4,093,141 $ 4.500 November 2029 (9) Warrants issued in February 2024 financing 13,086,151 $ 4.906 ** *The pre-funded warrants do not have an expiration date. **These warrants, the 2024 Warrants, have an exercise price of $ 4.906 per share (provided, however, that the purchaser may elect to exercise the warrants for pre-funded warrants in lieu of shares of common stock at an exercise price of $ 4.906 , minus $ 0.001 , the exercise price of each pre-funded warrant). These warrants are immediately exercisable for shares of common stock or pre-funded warrants in lieu thereof, and will expire on the earlier of (i) three and one-half years following the date of issuance and (ii) 30 days following our public disclosure of the acceptance of an NDA for cytisinicline by the FDA in a Day 74 Letter or equivalent correspondence. The agreements governing the above warrants include the following terms: • certain warrants have exercise prices which are subject to adjustment for certain events, including the issuance of stock dividends on our common stock and, in certain instances, the issuance of our common stock or instruments convertible into our common stock at a price per share less than the exercise price of the respective warrants (specifically those issued under the December 2019 Public Offering and November 2022 Private Placement); • warrant holders may exercise the warrants through a cashless exercise if, and only if, we do not have an effective registration statement then available for the issuance of the shares of our common stock. If an effective registration statement is available for the issuance of our common stock a holder may only exercise the warrants through a cash exercise; • the exercise price and the number and type of securities purchasable upon exercise of the warrants are subject to adjustment upon certain corporate events, including certain combinations, consolidations, liquidations, mergers, recapitalizations, reclassifications, reorganizations, stock dividends and stock splits, a sale of all or substantially all of our assets and certain other events; • in the case of certain warrants, in the event of an “extraordinary transaction” or a “fundamental transaction” (as such terms are defined in the respective warrant agreements), generally including any merger with or into another entity, sale of all or substantially all of the Company’s assets, tender offer or exchange offer, or reclassification of its common stock, in which the successor entity (as defined in the respective warrant agreements) that assumes the successor entity is not a publicly traded company, the Company or any successor entity will pay the warrant holder, at such holder’s option, exercisable at any time concurrently with or within 30 days after the consummation of the extraordinary transaction or fundamental transaction, an amount of cash equal to the value of such holder’s warrants as determined in accordance with the Black Scholes option pricing model and the terms of the respective warrant agreement. In some circumstances, we or successor entity may be obligated to make such payments regardless of whether the successor entity that assumes the warrants is a publicly traded company; and • with respect to the 2024 Warrants, in the event we consummate a “fundamental transaction,” as described in the 2024 Warrants and generally including a merger or consolidation with or into another person or other reorganization event in which our common shares are converted or exchanged for securities, cash or other property and we are not the surviving entity and in which our stockholders immediately prior to the merger or consolidation do not own, directly or indirectly, at least 50 % of the voting power of the surviving entity immediately after such merger or consolidation (excluding any merger effected solely to change the company’s name), or we sell, lease, license, assign, transfer, convey or otherwise dispose of all or substantially all of our assets or we or another person acquire 50 % or more of our outstanding shares of common stock, then following such event, the holders of the 2024 Warrants will be entitled to receive upon exercise of such 2024 Warrants the same kind and amount of securities, cash or property which the holders would have received had they exercised their 2024 Warrants immediately prior to such fundamental transaction. Any successor to us or surviving entity shall assume the obligations under the 2024 Warrants. Additionally, as more fully described in the 2024 Warrants, in the event of certain fundamental transactions, the holders of the 2024 Warrants will be entitled to receive consideration in an amount equal to the Black Scholes value of the 2024 Warrants on the date of consummation of such transaction. No warrants were exercised for the six months ended June 30, 2024. For the six months ended June 30, 2023 , warrants to purchase 98,333 shares, issued in the December 2019 financing, were exercised at a per share price of $ 2.31 , for proceeds of $ 0.2 million. As of June 30, 2024 , all of our outstanding warrants were classified as equity.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. COMMITMENTS AND CONTINGENCIES The following table summarizes our contractual obligations as of June 30, 2024 (in thousands): Total Less than 1 year 1-3 years 3-5 years More than 5 years Vancouver office operating lease $ 38 $ 38 $ — $ — $ — Total $ 38 $ 38 $ — $ — $ — Leases We have operating leases for our corporate offices. Operating leases with a term of 12 months or longer are included in ROU assets, other current liabilities, and operating lease liabilities on our consolidated balance sheets. Finance leases are included in property and equipment, other current liabilities, and other long-term liabilities on our consolidated balance sheets. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use the incremental borrowing rate of comparable companies from a representative peer group selected based on industry and market capitalization. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Vancouver lease arrangement On November 19, 2018, we entered into a lease agreement, or the Vancouver Lease, for office space in Vancouver, British Columbia, which commenced on February 1, 2019 and had a four-year term. Pursuant to the terms of the lease agreement, we rent approximately 2,367 square feet of office space. On December 16, 2022, we entered into an agreement to extend the lease for another two-year term, which commenced on February 1, 2023 . The annual rent is approximately $ 0.1 million. Consolidated rent expense relating to the Vancouver, British Columbia office, for the three and six months ended June 30, 2024 was $ 29,000 and $ 58,000 , respectively, and for the three and six months ended June 30, 2023 was $ 28,000 and $ 57,000 , respectively. Other information related to leases was as follows: Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows to operating leases $ 15 $ 13 $ 31 $ 28 Right-of-use assets obtained in exchange for lease obligations: Operating leases — — — — Weighted Average Remaining Lease Term Operating leases 0.58 years 1.58 years 0.58 years 1.58 years Weighted Average Discount Rate Operating leases 8.98 % 8.98 % 8.98 % 8.98 % Guarantees and Indemnifications We indemnify our officers, directors and certain consultants for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at its request in such capacity. The term of the indemnification period is equal to the officer’s or director’s lifetime. The maximum amount of potential future indemnification is unlimited; however, we have obtained director and officer insurance that limits our exposure and may enable us to recover a portion of any future amounts paid. We believe that the fair value of these indemnification obligations is minimal. Accordingly, we have no t recognized any liabilities relating to these obligations as of June 30, 2024. We have certain agreements with certain organizations with which we do business that contain indemnification provisions pursuant to which we typically agree to indemnify the party against certain types of third-party claims. We accrue for known indemnification issues when a loss is probable and can be reasonably estimated. There were no accruals for, or expenses related to, indemnification issues for any period presented.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	10. SUBSEQUENT EVENTS Contingent convertible debt On July 25, 2024, we entered into the New Debt Agreement, with SVB and Lender, pursuant to which the Lender provided term loans having an aggregate original principal amount of $ 10.0 million, with additional term loans of up to $ 10.0 million available upon the occurrence of certain events as provided for in the New Debt Agreement and further described below, or New Convertible Term Loan. Our obligations under the New Debt Agreement are secured by substantially all of our assets, other than intellectual property. The New Debt Agreement refinanced our Debt Agreement entered into on May 15, 2023 (see Note 7 “Convertible Debt”). Our obligations under the Debt Agreement and Convertible Term Loan were satisfied in full and the Debt Agreement and Convertible Term Loan were terminated in connection with the entrance into the New Debt Agreement and New Convertible Term Loan. The New Convertible Term Loan matures on December 1, 2027, which maturity date may be extended to June 1, 2028 upon the occurrence of certain events as provided for in the New Debt Agreement. The first tranche of the New Convertible Term Loan, which was advanced on July 25, 2024, has an aggregate original principal amount of $ 10.0 million. The Lender will further make available to us, upon our request: (a) on or prior to October 31, 2025, a second tranche of the New Convertible Term Loan having an aggregate principal amount of $ 5.0 million in the event that we receive written notice that the FDA has accepted for filing our NDA with respect to cytisinicline for a smoking cessation indication, or Additional Term Loan Event I, and (b) on or prior to December 31, 2025, a third tranche of the New Convertible Term Loan having an aggregate principal amount of $ 5.0 million, subject to the Lender’s sole discretion. Interest is calculated on the outstanding principal amount of the New Convertible Term Loan at a floating rate per annum equal to the greater of (i) 7.0 % and (ii) the prime rate minus 1.0 %, which interest shall be payable in cash monthly in arrears and shall be payable on the earlier to occur of (x) the first day of the first month following any extension of credit by the Lender for our credit, (y) the date of any prepayment pursuant to the New Debt Agreement, or (z) the maturity date. The New Convertible Term Loan will be “interest-only” until December 31, 2025. The “interest-only” period may be extended to June 30, 2026, provided that (i) after the Effective Date, but prior to December 31, 2025, we have received at least $ 40,000,000 in net cash proceeds from the sale and issuance of equity interests and (ii) the conditions of Additional Term Loan Event I have been satisfied. Subject to certain terms and conditions, the conversion feature grants the Lender or, pursuant to an assignment, any designee thereof, or Conversion Right Holders, the right to convert part or all of the outstanding aggregate original principal amount of the New Convertible Term Loan, plus accrued and unpaid interest, into shares of our common stock, or Initial Voluntary Conversion, at a conversion price equal to $ 7.00 , subject to customary adjustment provisions. The Conversion Rights Holders have the further right to convert part or all of the outstanding principal amount of the second and third tranches of the New Convertible Term Loan, plus accrued and unpaid interest, into shares of our common stock at a conversion price equal to the greater of (i) $ 4.854 , subject to customary adjustment provisions, and (ii) the lower of (a) 150 % of the average of the closing sale price of our common stock during the 10 trading days preceding the effective date of such tranche and (b) 150 % of the closing sale price of our common stock on the trading day immediately preceding the effective date of such tranche, or Subsequent Conversion Price. The conversion rights may be exercised at each Conversion Right Holder's option any time prior to repayment of the New Convertible Term Loan; provided, however, that a Voluntary Conversion will not be permitted without the agreement of the relevant Conversion Right Holder and us if the sum of the amount of debt to be converted; and the aggregate amount of debt previously converted pursuant to any Voluntary Conversion, divided by the aggregate of all debt that is then outstanding or that has been repaid other than by conversion exceeds 50 %. Additionally, the outstanding principal of the New Convertible Term Loan, plus accrued and unpaid interest, will automatically be converted into Conversion Shares at the Conversion Price on such date if any, when the closing price per share of our common stock has been equal to or greater than (a) in the case of the outstanding aggregate original principal amount of the New Convertible Term Loan, plus accrued and unpaid interest, $ 24.00 or, (b) in the case of the outstanding principal amount of the second and third tranches of the New Convertible Term Loan, plus accrued and unpaid interest, three times the applicable Subsequent Conversion Price, in each case for the thirty consecutive trading days prior to such date, and the Liquidity Conditions (as defined in the Debt Agreement) have been satisfied. The New Convertible Term Loan may be repaid at our election and upon notice to the Agent by paying the Lender an amount equal to (i) a prepayment fee equal to (a) 3.0 % of the aggregate outstanding principal balance if such prepayment occurs on or prior to the first anniversary of the New Convertible Term Loan, (b) 2.0 % of the aggregate outstanding principal balance if such prepayment occurs after the first anniversary, but on or prior to the second anniversary, of the New Convertible Term Loan or (c) 1.0 % of the aggregate outstanding principal balance if such prepayment occurs after the second anniversary of the New Convertible Term Loan and before the maturity date; (ii) 4.0 % of the original aggregate principal amount of the New Convertible Term Loan and (iii) all other sums due and payable under the New Convertible Term Loan. The Debt Agreement contains customary affirmative and restrictive covenants, including covenants regarding the incurrence of additional indebtedness or liens, investments, transactions with affiliates, delivery of financial statements, payment of taxes, maintenance of insurance, dispositions of property, mergers or acquisitions, among other customary covenants. We are also restricted from paying dividends or making other distributions or payments on its capital stock, subject to limited exceptions. The New Debt Agreement also includes customary representations and warranties, events of default and termination provisions. The Lender may not engage in any short sales of, or other hedging transactions in, our common stock while any amounts are outstanding under the New Debt Agreement. In connection with the New Debt Agreement, we entered into a Registration Rights Agreement, or RRA, with the Lender, pursuant to which we are required to register for resale shares of our common stock issuable to the Conversion Right Holders upon the conversion of outstanding debt under the New Debt Agreement within 30 days of the date of the RRA. Our obligations under the RRA will terminate with respect to a holder of applicable registrable securities if, as of the date we would be required to provide written notice of such registration, (x) the aggregate number of registrable securities then issued and issuable to such holder and to such holder’s affiliates, together with all other shares then held beneficially and/or of record by such holder and its affiliates, does not exceed 7.0 % of our then-total shares issued and outstanding (calculated including all such registrable securities and other shares), or (y) we and such holder mutually reasonably agree that all registrable securities then issued and issuable to such holder and its affiliates may then be sold by such holder without the requirement to be in compliance with Rule 144 promulgated under the Securities Act, or Rule 144, and otherwise without restriction or limitation pursuant to Rule 144.

Accounting Policies (Policies)

Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Short-Term Investments	Short-Term Investments Short-term investments consist of financial instruments purchased with an original maturity of greater than three months and less than one year. We consider our short-term investments as available-for-sale and carry them at fair value, with unrealized gains and losses, if any, reported as accumulated other comprehensive income or loss, which is a separate component of stockholders’ equity. Realized gains and losses on the sale or impairment, if any, of these securities, are recognized in net income or loss. The cost of investments sold is based on the specific identification method.
Fair Value of Financial Instruments	Fair value of financial instruments The fair value of our marketable securities is based on quoted market prices and trade data for comparable securities.

Intangibles (Tables)

Intangibles (Tables)	6 Months Ended
	Jun. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Intangible Assets	The components of intangible assets were as follows: June 30, 2024 December 31, 2023 Gross Carrying Accumulated Net Carrying Gross Carrying Accumulated Net Carrying Value Amortization Value Value Amortization Value License Agreements $ 3,117 $ ( 2,031 ) $ 1,086 $ 3,117 $ ( 1,920 ) $ 1,197
Estimated Future Amortization Expense Related to Intangible Assets	The following table outlines the estimated future amortization expense related to intangible assets held as of June 30, 2024 : Year Ending December 31, 2024 112 2025 223 2026 223 2027 223 Thereafter 305 Total $ 1,086

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents information about our assets and liabilities that are measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques we utilized to determine such fair value (in thousands): June 30, 2024 Level 1 Level 2 Level 3 Total Assets Money market securities (cash equivalents) $ 14,466 $ — $ — $ 14,466 Restricted cash 20 — — 20 US government securities — 27,093 — 27,093 Corporate bonds — 18,478 — 18,478 Commercial paper — 986 — 986 Total assets $ 14,486 $ 46,557 $ — $ 61,043 Liabilities Convertible debt $ — 17,585 $ — $ 17,585 Contingent consideration — — 637 637 Total liabilities $ — $ 17,585 $ 637 $ 18,222
Summary of Cash Equivalents	Cash equivalents consist of the following (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated June 30, 2024 Cost Gains Losses Fair Value Money market securities $ 14,466 $ — $ — $ 14,466 Total cash equivalents $ 14,466 $ — $ — $ 14,466 Money market securities (restricted cash) $ 20 $ — $ — $ 20 Total restricted cash $ 20 $ — $ — $ 20
Schedule of Corporate Bonds and Commercial Paper	Gross Gross Amortized Unrealized Unrealized Estimated June 30, 2024 Cost Gains Losses Fair Value US government securities $ 27,100 $ — $ ( 7 ) $ 27,093 Corporate bonds 18,482 — ( 4 ) 18,478 Commercial paper 986 — — 986 Total short term investments $ 46,568 $ — $ ( 11 ) $ 46,557
Schedule of Aggregate Fair Value of Principal Amount of Convertible Debt	The aggregate fair value of the principal amount of the convertible debt is a Level 2 fair value measurement. June 30, 2024 December 31, 2023 Principal Carrying Fair Principal Carrying Fair Amount Value Value Amount Value Value December 2021 Convertible Debt $ 15,000 $ 17,608 $ 17,585 $ 15,000 $ 16,662 $ 16,652 As of June 30, 2024 and December 31, 2023, the Convertible Term Loan balance, including the Convertible Debt balance, was comprised of the following: June 30, December 31, 2024 2023 Convertible Term Loan Information Principal $ 15,000 $ 15,000 Transaction Costs ( 5 ) ( 5 ) Accrued paid-in-kind interest 2,935 2,311 Discount on modification of debt ( 1,074 ) ( 1,074 ) Accretion of discount on modification of debt 752 430 17,608 16,662
Schedule of Changes in Fair Value of Liabilities	The following table presents the changes in fair value of our total Level 3 financial liabilities for the six months ended June 30, 2024: Balance at Change in Balance at (in thousands) December 31, 2023 Fair Value June 30, 2024 Contingent consideration $ 528 $ 109 $ 637

Convertible Debt (Tables)

Convertible Debt (Tables)	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Schedule of Aggregate Fair Value of Principal Amount of Convertible Debt	The aggregate fair value of the principal amount of the convertible debt is a Level 2 fair value measurement. June 30, 2024 December 31, 2023 Principal Carrying Fair Principal Carrying Fair Amount Value Value Amount Value Value December 2021 Convertible Debt $ 15,000 $ 17,608 $ 17,585 $ 15,000 $ 16,662 $ 16,652 As of June 30, 2024 and December 31, 2023, the Convertible Term Loan balance, including the Convertible Debt balance, was comprised of the following: June 30, December 31, 2024 2023 Convertible Term Loan Information Principal $ 15,000 $ 15,000 Transaction Costs ( 5 ) ( 5 ) Accrued paid-in-kind interest 2,935 2,311 Discount on modification of debt ( 1,074 ) ( 1,074 ) Accretion of discount on modification of debt 752 430 17,608 16,662

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Summary of Stock Options Activity	Stock option transactions and the number of stock options outstanding are summarized below: Number of Weighted Optioned Average Common Exercise Shares Price Balance, December 31, 2023 1,461,980 $ 12.12 Granted 466,500 4.55 Expired ( 41 ) 24,184.44 Balance, June 30, 2024 1,928,439 $ 9.78
Summary of Fair Value of Each Stock Award for Employees and Directors	The fair value of each stock award for employees and directors is estimated on the grant date and for consultants at each reporting period, using the Black-Scholes option-pricing model based on the weighted-average assumptions noted in the following table: Six Months Ended June 30, 2024 2023 Risk-free interest rates 4.00 % 3.60 % Expected dividend yield 0 % 0 % Expected life 5.65 years 5.75 years Expected volatility 90.15 % 115.19 % Forfeiture rate 0.00 % 0.00 %
Summary of Share-Based Compensation Expense	The results for the periods set forth below included share-based compensation expense for stock options, restricted stock units and employee share purchase plan compensation expenses in the following expense categories of the consolidated statements of loss (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Research and development $ 486 $ 403 $ 899 $ 786 General and administrative $ 968 786 1,843 1,489 Total stock-based compensation $ 1,454 $ 1,189 $ 2,742 $ 2,275
Summary of Restricted Stock Unit Award Activity	The following table summarizes our restricted stock unit award activity during the six months ended June 30, 2024: Weighted Number Average of Grant Date Shares Fair Value Balance, December 31, 2023 507,875 $ 5.65 Granted 721,000 4.55 Released ( 113,125 ) 8.26 Balance, June 30, 2024 1,115,750 $ 4.67
Summary of Outstanding Warrants	The following is a summary of outstanding warrants to purchase common stock as of June 30, 2024: Total Outstanding Exercise and price per Exercisable Share Expiration Date (1) Warrants issued in May 2019 financing 60,000 $ 90.000 May 2025 (2) Warrants issued in December 2019 financing 510,924 $ 2.310 December 2024 (3) Warrants issued in April 2020 financing 182,461 $ 7.240 April 2025 (4) Warrants issued in April 2020 financing 24,375 $ 7.320 April 2025 (5) Warrants issued in April 2020 financing 25,270 $ 7.590 April 2025 (6) Pre-Funded warrants issued in August 2020 financing 142,857 $ 0.001 * (7) Warrants issued in December 2020 financing 50,000 $ 8.750 December 2025 (8) Warrants issued in November 2022 financing 4,093,141 $ 4.500 November 2029 (9) Warrants issued in February 2024 financing 13,086,151 $ 4.906 ** *The pre-funded warrants do not have an expiration date. **These warrants, the 2024 Warrants, have an exercise price of $ 4.906 per share (provided, however, that the purchaser may elect to exercise the warrants for pre-funded warrants in lieu of shares of common stock at an exercise price of $ 4.906 , minus $ 0.001 , the exercise price of each pre-funded warrant). These warrants are immediately exercisable for shares of common stock or pre-funded warrants in lieu thereof, and will expire on the earlier of (i) three and one-half years following the date of issuance and (ii) 30 days following our public disclosure of the acceptance of an NDA for cytisinicline by the FDA in a Day 74 Letter or equivalent correspondence.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2024
Operating Leased Assets [Line Items]
Summary of Contractual Obligations	The following table summarizes our contractual obligations as of June 30, 2024 (in thousands): Total Less than 1 year 1-3 years 3-5 years More than 5 years Vancouver office operating lease $ 38 $ 38 $ — $ — $ — Total $ 38 $ 38 $ — $ — $ —
Summary of Other Information Related to Leases	Other information related to leases was as follows: Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows to operating leases $ 15 $ 13 $ 31 $ 28 Right-of-use assets obtained in exchange for lease obligations: Operating leases — — — — Weighted Average Remaining Lease Term Operating leases 0.58 years 1.58 years 0.58 years 1.58 years Weighted Average Discount Rate Operating leases 8.98 % 8.98 % 8.98 % 8.98 %

Nature of Business, Basis of _2

Nature of Business, Basis of Presentation and Liquidity Risk - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Nature Of Business And Basis Of Presentation [LineItems]
Accumulated deficit	$ (180,706)				$ (180,706)		$ (165,751)
Cash,cash equivalents and short-term investments	14,756				14,756		$ 15,546
Cash,cash equivalents and short-term investments	61,300				61,300
Working capital	48,800				48,800
Net loss	$ (8,461)	$ (6,494)	$ (8,239)	$ (8,992)	(14,955)	$ (17,231)
Net cash used in operating activities					$ 10,209	$ 14,979

Government Grant - Additional I

Government Grant - Additional Information (Details) - USD ($)		1 Months Ended	6 Months Ended
	Aug. 01, 2021	Jun. 30, 2022	Jun. 30, 2024	Dec. 31, 2023
Government Grant [Line Items]
Grant receivable				$ 111,000
NIDA
Government Grant [Line Items]
Grant awarded	$ 300,000	$ 2,500,000
NIDA/NIH
Government Grant [Line Items]
Reduction in R&D expense			$ 16,000
Reimbursements received.			$ 2,500,000

Intangibles - Additional Inform

Intangibles - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	May 18, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, Fair Value					$ 3,100,000
Intangible assets, Useful life					14 years
License agreement amortization expense	$ 100,000	$ 100,000	$ 100,000	$ 100,000
Impairment of intangible assets			$ 0

Intangibles - Components of Int

Intangibles - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Finite Lived Intangible Assets [Line Items]
Intangible assets, Net Carrying Value	$ 1,086	$ 1,197
License Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Value	3,117	3,117
Intangible assets, Accumulated Amortization	(2,031)	(1,920)
Intangible assets, Net Carrying Value	$ 1,086	$ 1,197

Intangibles - Estimated Future

Intangibles - Estimated Future Amortization Expense Related to Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2024	$ 112
2025	223
2026	223
2027	223
Thereafter	305
Intangible assets, Net Carrying Value	$ 1,086	$ 1,197

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
	May 14, 2015	Jun. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash		$ 100	$ 100
Fair value of the contingent consideration		637	637	$ 528
Loss on contingent consideration		57	109
Sopharma [Member] | Share Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of outstanding shares acquired	75%
Cash	$ 2,000
Deferred payment	$ 2,000
Fair value of the contingent consideration		600	600
Loss on contingent consideration		$ 100	$ 100

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Maximum maturity period of cash and cash equivalents	90 days
Cash	$ 100
Cash equivalents	14,466
Custodian deposits	$ 58,800
Share Purchase Agreement [Member] | Measurement Input, Probability of Success [Member] | Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration, Liability, Measurement Input [Extensible Enumeration]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Measurement Input	0.672
Share Purchase Agreement [Member] | Measurement Input, Discount Rate [Member] | Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Business Combination, Contingent Consideration, Liability, Measurement Input [Extensible Enumeration]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Measurement Input	0.38
Sweep Account [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Cash equivalents	$ 1,700
Maximum [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Maturity period of securities	1 year

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Measurements, Recurring [Member]
Assets
Total assets	$ 61,043
Liabilities
Total liabilities	18,222
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Assets
Total assets	18,478
Fair Value, Measurements, Recurring [Member] | Convertible Debt [Member]
Liabilities
Total liabilities	17,585
Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Liabilities
Total liabilities	637
Fair Value, Measurements, Recurring [Member] | US Government Securities [Member]
Assets
Total assets	27,093
Fair Value, Measurements, Recurring [Member] | Money market securities (cash equivalents) [Member]
Assets
Total assets	14,466
Fair Value, Measurements, Recurring [Member] | Restricted cash [Member]
Assets
Total assets	20
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Assets
Total assets	986
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total assets	14,486
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Money market securities (cash equivalents) [Member]
Assets
Total assets	14,466
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Restricted cash [Member]
Assets
Total assets	20
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total assets	46,557
Liabilities
Total liabilities	17,585
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Assets
Total assets	18,478
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Convertible Debt [Member]
Liabilities
Total liabilities	17,585
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | US Government Securities [Member]
Assets
Total assets	27,093
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Assets
Total assets	986
Level 3 [Member] | Contingent Consideration [Member]
Liabilities
Total liabilities	637	$ 528
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Total liabilities	637
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Liabilities
Total liabilities	$ 637

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Cash Equivalents (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, amortized cost and estimated fair value	$ 14,466
Restricted cash, amortized cost and estimated fair value	20
Money market securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, amortized cost and estimated fair value	14,466
Restricted cash, amortized cost and estimated fair value	$ 20

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Corporate Bonds and Commercial Paper (Details) $ in Thousands	Jun. 30, 2024 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 46,568
Gross Unrealized Losses	(11)
Estimated Fair Value	46,557
US Government Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	27,100
Gross Unrealized Losses	(7)
Estimated Fair Value	27,093
Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	18,482
Gross Unrealized Losses	(4)
Estimated Fair Value	18,478
Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	986
Estimated Fair Value	$ 986

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Aggregate Fair Value of Principal Amount of Convertible Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Convertible Debt, Principal Amount	$ 15,000	$ 15,000
Convertible Debt, Carrying Value	17,608	16,662
Convertible Debt, Fair Value	$ 17,585	$ 16,652

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Changes in Fair Value of Liabilities (Details) - Level 3 [Member] - Contingent Consideration [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of total financial liabilities	$ 528
Liabilities, Fair Value Adjustment	109
Fair value of total financial liabilities	$ 637

Convertible Debt - Additional I

Convertible Debt - Additional Information (Details) - USD ($)			6 Months Ended
	Jul. 25, 2024	May 15, 2023	Jun. 30, 2024	Dec. 31, 2025	Oct. 31, 2025	Dec. 31, 2023	Apr. 26, 2022	Dec. 22, 2021
Convertible Debt [Line Items]
Convertible debt principal amount			$ 15,000,000			$ 15,000,000
Convertible debt compound interest		7%
Maximum [Member]
Convertible Debt [Line Items]
Convertible debt compound interest		2.25%
Prime Rate Minus 1.0% [Member]
Convertible Debt [Line Items]
Convertible debt, interest rate		1%
SVB [Member] | Contingent Convertible Debt Agreement [Member]
Convertible Debt [Line Items]
Convertible debt principal amount								$ 25,000,000
SVB [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Debt [Member]
Convertible Debt [Line Items]
Convertible debt principal amount								$ 15,000,000
SVB [Member] | Contingent Convertible Debt Agreement [Member] | Non-Convertible Term Loans [Member]
Convertible Debt [Line Items]
Convertible debt principal amount							$ 10,000,000
Loan amount drawn			$ 0
Loan agreement expiration date			Apr. 30, 2023
SVB [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Term Loan [Member]
Convertible Debt [Line Items]
Convertible debt principal amount		$ 16,600,000
SVB and Lender [Member] | Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member]
Convertible Debt [Line Items]
Convertible debt principal amount	$ 10,000,000
SVB and Lender [Member] | Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Term Loan [Member]
Convertible Debt [Line Items]
Convertible debt principal amount	$ 10,000,000			$ 5,000,000	$ 5,000,000
Convertible debt compound interest	7%
SVB and Lender [Member] | Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Term Loan [Member] | Prime Rate Minus 1.0% [Member]
Convertible Debt [Line Items]
Convertible debt, interest rate	1%

Convertible Debt - Schedule of

Convertible Debt - Schedule of Convertible Term Loan Balance Including Convertible Debt Balance (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Convertible Term Loan Information
Convertible Debt, Principal Amount	$ 15,000	$ 15,000
Transaction Costs	(5)	(5)
Accrued paid-in-kind interest	2,935	2,311
Discount on modification of debt	(1,074)	(1,074)
Accretion of discount on modification of debt	752	430
Convertible debt	$ 17,608	$ 16,662

Common Stock - Authorized - Add

Common Stock - Authorized - Additional Information (Detail) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Common stock, shares authorized	150,000,000	150,000,000
Common stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000
Preferred stock, par value	$ 0.001

Common Stock - Issued and Outst

Common Stock - Issued and Outstanding Shares - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended			6 Months Ended		26 Months Ended
	Feb. 29, 2024	Feb. 29, 2024	May 31, 2023	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Feb. 29, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option exercises, Shares				0		0	0	0
Restricted stock unit settlements				113,125		139,750	113,125	139,750
Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock unit settlements				113,125		139,750
At-the-Market Sales Agreement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares issued	0				0				200,000
Gross proceeds									$ 1.5
Direct Offering [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Gross proceeds from issuance of common stock		$ 60
Placement agent fees and offering expenses		3.9
Proceeds from issuance of common stock		$ 56.1	$ 15.3
Direct Offering [Member] | Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares issued		13,086,151	3,000,000
Common stock, price per share	$ 4.585	$ 4.585	$ 5.5						$ 4.585
Private Placement [Member] | Pre Funded Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price per unit of warrant	$ 0.001	$ 0.001		$ 0.001			$ 0.001		$ 0.001
Private Placement [Member] | Common Stock [Member] | Pre Funded Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants to purchase common stock	13,086,151	13,086,151							13,086,151
Exercise price per unit of warrant	$ 4.906	$ 4.906		$ 4.906			$ 4.906		$ 4.906

Common Stock - Stock Options -

Common Stock - Stock Options - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for options currently outstanding	1,928,439	1,928,439		1,461,980
Number of shares granted		466,500
Unrecognized compensation expense related to stock options granted	$ 3.5	$ 3.5
Anti-dilutive securities excluded from earning per share computation		21,219,368	7,090,100
Warrant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Anti-dilutive securities excluded from earning per share computation		18,175,179
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period, restricted stock awards		1 year 7 months 13 days
Anti-dilutive securities excluded from earning per share computation		1,928,439
Stock Options [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
Stock Options [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period		7 years
Stock Options [Member] | Minimum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		1 year
Stock Options [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period		10 years
Stock Options [Member] | Maximum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
Restricted Stock Unit [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted shares reserved for issuance under incentive plan	1,115,750	1,115,750
Award vesting period		4 years
Weighted-average period, restricted stock awards		1 year 3 months
Anti-dilutive securities excluded from earning per share computation		1,115,750
2018 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	61,761	61,761
Award expiration period		10 years
2018 Equity Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2018 Equity Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		1 year
2018 Equity Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
2018 Equity Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2018 Equity Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	2,667,416	2,667,416
Common shares reserved for options currently outstanding	1,489,905	1,489,905
New Employee Inducement Grants [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for options currently outstanding	135,000	135,000
Award expiration period		10 years
Number of shares granted	0	0
2017 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period		10 years
2017 Equity Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2017 Equity Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		1 year
2017 Equity Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
2017 Equity Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2017 Equity Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	13,156	13,156
2010 Performance Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period		10 years
2010 Performance Incentive Plan [Member] | Minimum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2010 Performance Incentive Plan [Member] | Minimum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		1 year
2010 Performance Incentive Plan [Member] | Maximum [Member] | Employees and Consultants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
2010 Performance Incentive Plan [Member] | Maximum [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2010 Performance Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	128	128
2023 Non Employee Director Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	9,750	9,750
Award expiration period		10 years
2023 Non Employee Director Equity Incentive Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		1 year
2023 Non Employee Director Equity Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		3 years
2023 Non Employee Director Equity Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common shares reserved for issuance under incentive plan	300,000	300,000
Common shares reserved for options currently outstanding	290,250	290,250

Common Stock - Summary of Stock

Common Stock - Summary of Stock Options Activity (Detail)	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Optioned Common Shares, Beginning Balance | shares	1,461,980
Number of Optioned Common Shares, Granted | shares	466,500
Number of Optioned Common Shares, Expired | shares	(41)
Number of Optioned Common Shares, Ending Balance | shares	1,928,439
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 12.12
Weighted Average Exercise Price, Granted | $ / shares	4.55
Weighted Average Exercise Price, Expired | $ / shares	24,184.44
Weighted Average Exercise Price, Ending Balance | $ / shares	$ 9.78

Common Stock - Summary of Fair

Common Stock - Summary of Fair Value of Each Stock Award for Employees and Directors (Detail)	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Risk-free interest rates	4%	3.60%
Expected dividend yield	0%	0%
Expected life	5 years 7 months 24 days	5 years 9 months
Expected volatility	90.15%	115.19%
Forfeiture rate	0%	0%

Common Stock - Summary of Share

Common Stock - Summary of Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 1,454	$ 1,189	$ 2,742	$ 2,275
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	486	403	899	786
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 968	$ 786	$ 1,843	$ 1,489

Common Stock - Restricted Stock

Common Stock - Restricted Stock Unit Awards - Additional Information (Detail) - Restricted Stock Unit [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			4 years
Stock based compensation expense	$ 0.6	$ 0.5	$ 1.1	$ 1
Total unrecognized compensation expense related to the Company's restricted stock unit awards	$ 2.5		$ 2.5
Weighted-average period, restricted stock awards			1 year 3 months

Common Stock - Summary of Restr

Common Stock - Summary of Restricted Stock Unit Award Activity (Detail) - Restricted Stock Unit [Member]	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Beginning Balance | shares	507,875
Number of Shares, Granted | shares	721,000
Number of Shares, Released | shares	(113,125)
Number of Shares, Ending Balance | shares	1,115,750
Weighted-Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 5.65
Weighted-Average Grant Date Fair Value, Granted | $ / shares	4.55
Weighted-Average Grant Date Fair Value, Released | $ / shares	8.26
Weighted-Average Grant Date Fair Value, Ending Balance | $ / shares	$ 4.67

Common Stock - Employee Share P

Common Stock - Employee Share Purchase Plan - Additional Information (Detail) - Employee Share Purchase Plan - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares authorized to purchased			556,270
Number of shares purchased	0	0
Stock based compensation expense		$ 0.1	$ 0.1

Common Stock - Summary of Outst

Common Stock - Summary of Outstanding Warrants (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Warrants Issued in May 2019 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	60,000
Exercise price per Share	$ 90
Expiration Date	2025-05
Warrants Issued in December 2019 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	510,924
Exercise price per Share	$ 2.310	$ 2.31
Expiration Date	2024-12
Warrants Issued in April 2020 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	182,461
Exercise price per Share	$ 7.240
Expiration Date	2025-04
Warrants Issued in April 2020 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	24,375
Exercise price per Share	$ 7.320
Expiration Date	2025-04
Warrants Issued in April 2020 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	25,270
Exercise price per Share	$ 7.590
Expiration Date	2025-04
Pre-Funded Warrants Issued in August 2020 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	142,857
Exercise price per Share	$ 0.001
Warrants Issued in December 2020 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	50,000
Exercise price per Share	$ 8.750
Expiration Date	2025-12
Warrants Issued in November 2022 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	4,093,141
Exercise price per Share	$ 4.5
Expiration Date	2029-11
Warrants Issued in February 2024 [Member]
Class of Warrant or Right [Line Items]
Total Outstanding and Exercisable	13,086,151
Exercise price per Share	$ 4.906

Common Stock - Stock Warrants -

Common Stock - Stock Warrants - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Feb. 29, 2024
Class of Warrant or Right [Line Items]
Proceeds from exercise of warrants		$ 227
Percentage of voting power	50%
Warrants Issued in December 2019 [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase common stock	0	98,333
Exercise price per share of warrant	$ 2.310	$ 2.31
Proceeds from exercise of warrants		$ 200
Pre Funded Warrants
Class of Warrant or Right [Line Items]
Percentage of outstanding shares of common stock	50%
Pre Funded Warrants | Private Placement [Member]
Class of Warrant or Right [Line Items]
Exercise price per share of warrant	$ 0.001		$ 0.001
Pre Funded Warrants | Common Stock [Member] | Private Placement [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase common stock			13,086,151
Exercise price per share of warrant	$ 4.906		$ 4.906

Commitments and Contingencies -

Commitments and Contingencies - Summary of Contractual Obligations (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Contractual Obligation Fiscal Year Maturity Schedule [Line Items]
Total	$ 38
Less than 1 year	38
Vancouver Office Operating Lease [Member]
Contractual Obligation Fiscal Year Maturity Schedule [Line Items]
Total	38
Less than 1 year	$ 38

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail)			3 Months Ended		6 Months Ended
	Dec. 16, 2022	Nov. 19, 2018 USD ($) ft²	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)
Other Commitments [Line Items]
Consolidated rent expense			$ 29,000	$ 28,000	$ 58,000	$ 57,000
Indemnification obligations			$ 0		0
Expenses related to indemnification issues					$ 0
Vancouver Office Operating Lease [Member] | Vancouver, British Columbia [Member]
Other Commitments [Line Items]
Lease agreement commencement date	Feb. 01, 2023	Feb. 01, 2019
Area of office space leased | ft²		2,367
Operating lease, term of contract		4 years
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Operating lease, extension term	2 years
Annual rent expense		$ 100,000

Commitments and Contingencies_3

Commitments and Contingencies - Summary of Other Information Related to Leases (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows to operating leases	$ 15	$ 13	$ 31	$ 28
Right-of-use assets obtained in exchange for lease obligations:
Weighted Average Remaining Lease Term Operating leases	6 months 29 days	1 year 6 months 29 days	6 months 29 days	1 year 6 months 29 days
Weighted Average Discount Rate Operating leases	8.98%	8.98%	8.98%	8.98%

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)			4 Months Ended
	Jul. 25, 2024 USD ($) Days $ / shares	May 15, 2023	Dec. 31, 2025 USD ($)	Oct. 31, 2025 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Subsequent Event [Line Items]
Convertible debt principal amount					$ 15,000,000	$ 15,000,000
Convertible debt, stated rate		7%
Prime Rate Minus 1.0% [Member]
Subsequent Event [Line Items]
Convertible debt, interest rate		1%
Subsequent Event [Member] | Convertible Term Loan [Member]
Subsequent Event [Line Items]
Debt conversion description	conversion price equal to the greater of (i) $4.854, subject to customary adjustment provisions, and (ii) the lower of (a) 150% of the average of the closing sale price of our common stock during the 10 trading days preceding the effective date of such tranche and (b) 150% of the closing sale price of our common stock on the trading day immediately preceding the effective date of such tranche, or Subsequent Conversion Price.
Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | SVB and Lender [Member]
Subsequent Event [Line Items]
Convertible debt principal amount	$ 10,000,000
Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Term Loan [Member] | SVB and Lender [Member]
Subsequent Event [Line Items]
Convertible debt principal amount	$ 10,000,000		$ 5,000,000	$ 5,000,000
Maturity date	Jun. 01, 2028
Net cash proceeds from the sale and issuance of equity securities			$ 40,000,000
Convertible debt, stated rate	7%
Stock trigger price | $ / shares	$ 24
Threshold consecutive trading days | Days	10
Conversion price percentage of average closing sale price	150%
Conversion price percentage of closing trading share price	150%
Threshold percentage of conversion amount of debt	50%
Prepayment fee percentage on or after first anniversary	3%
Prepayment fee percentage occurs after first anniversary but on or prior to the second anniversary	2%
Prepayment fee percentage after second anniversary before maturity	1%
Prepayment fee percentage on original aggregate principal	4%
Conversion price per share | $ / shares	$ 7
Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | Convertible Term Loan [Member] | SVB and Lender [Member] | Minimum [Member]
Subsequent Event [Line Items]
Conversion price per share | $ / shares	$ 4.854
Subsequent Event [Member] | Contingent Convertible Debt Agreement [Member] | Prime Rate Minus 1.0% [Member] | Convertible Term Loan [Member] | SVB and Lender [Member]
Subsequent Event [Line Items]
Convertible debt, interest rate	1%
Subsequent Event [Member] | Registration Rights Agreement [Member] | SVB and Lender [Member]
Subsequent Event [Line Items]
Share holding percentage of shares issued and outstanding	7%
Debt agreement period	30 days