eFFECTOR Therapeutics (EFTR) 10-Q 9 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Registrant Name	eFFECTOR Therapeutics, Inc.
Entity Central Index Key	0001828522
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		4,704,409
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-39866
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3306396
Entity Address, Address Line One	142 North Cedros Avenue
Entity Address, Address Line Two	Suite B
Entity Address, City or Town	Solana Beach
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92075
City Area Code	858
Local Phone Number	925-8215
Document Quarterly Report	true
Document Transition Report	false
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	EFTR
Title of 12(b) Security	Common stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Warrant [Member]
Document Information [Line Items]
Trading Symbol	EFTRW
Title of 12(b) Security	Warrants to purchase common stock
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 15,508	$ 14,875
Short-term investments	9,875	3,495
Prepaid expenses and other current assets	867	1,468
Total current assets	26,250	19,838
Property and equipment, net	190	140
Operating lease right-of-use assets	225	53
Other assets	466	513
Total assets	27,131	20,544
Current liabilities:
Accounts payable	1,713	2,330
Accrued expenses	3,787	2,921
Current term loans, net	18,916	19,385
Accrued final payment on term loans, current	1,100	1,100
Lease liabilities, current portion	53	60
Total current liabilities	25,569	25,796
Other accrued liabilities, non-current	516	503
Non-current warrant liability	40	40
Non-current lease liabilities	179	0
Total liabilities	26,304	26,339
Commitments and contingencies
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 100,000,000 shares authorized at March 31, 2024 and December 31, 2023; zero shares issued and outstanding as March 31, 2024 and December 31, 2023	0	0
Common stock, $0.0001 par value; 40,000,000 shares authorized at March 31, 2024 and December 31, 2023; 3,914,309 shares issued and 3,902,309 shares issued and outstanding as of March 31, 2024; 2,994,679 shares issued and 2,982,679 shares issued and outstanding as of December 31, 2023	0	0
Additional paid-in capital	189,038	173,582
Accumulated other comprehensive income (loss)	0	0
Accumulated deficit	(188,211)	(179,377)
Total stockholders' equity (deficit)	827	(5,795)
Total liabilities and stockholders' equity (deficit)	$ 27,131	$ 20,544

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock price per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	3,914,309	2,994,679
Common stock, shares outstanding	3,902,309	2,982,679

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses:
Research and development	$ 5,306	$ 6,609
General and administrative	3,090	2,927
Total operating expenses	8,396	9,536
Operating loss	(8,396)	(9,536)
Other income (expense)
Interest income	323	226
Interest expense	(749)	(689)
Other expense	(12)	(15)
Total other income (expense)	(438)	(478)
Net loss	(8,834)	(10,014)
Comprehensive income (loss):
Net Income (Loss)	(8,834)	(10,014)
Other comprehensive income	0	19
Comprehensive loss	$ (8,834)	$ (9,995)
Net income (loss) per share attributable to common shareholders:
Net loss per share - Basic	$ (2.16)	$ (5.96)
Net loss per share - diluted	$ (2.16)	$ (5.96)
Weighted-average common shares outstanding:
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Weighted average common shares outstanding - diluted	4,081,580	1,680,032

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2022	$ 3,896	$ 0	$ 147,480	$ (18)	$ (143,566)
Balance, shares at Dec. 31, 2022		1,667,602
Stock option exercises	0
Issuance of common stock, net of issuance costs, value	119		119
Issuance of common stock, net of issuance costs, shares		16,433
Stock-based compensation expense	1,167		1,167
Unrealized loss on short-term investments	19			19
Net Income (Loss)	(10,014)				(10,014)
Balance at Mar. 31, 2023	(4,813)	$ 0	148,766	1	(153,580)
Balance, shares at Mar. 31, 2023		1,684,035
Balance at Dec. 31, 2023	$ (5,795)	$ 0	173,582		(179,377)
Balance, shares at Dec. 31, 2023	2,982,679	2,982,679
Stock Option And Prefunded Warrant Exercises shares		497,834
Issuance of common stock, net of issuance costs, value	$ 14,446		14,446
Issuance of common stock, net of issuance costs, shares		421,796
Stock-based compensation expense	1,010		1,010
Net Income (Loss)	(8,834)				(8,834)
Balance at Mar. 31, 2024	$ 827	$ 0	$ 189,038	$ 0	$ (188,211)
Balance, shares at Mar. 31, 2024	3,902,309	3,902,309

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities:
Net Income (Loss)	$ (8,834)	$ (10,014)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense	28	28
Accretion of discount and amortization of premium on investments, net	(60)	(119)
Stock-based compensation	1,010	1,167
Other expense related to equity purchase agreement	12	15
Non-cash interest expense	87	76
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	267	(180)
Other non-current assets	53	48
Accounts payable	(716)	2,225
Accrued expenses	875	(886)
Operating lease right-of-use assets and liabilities, net	0	3
Net cash used in operating activities	(7,278)	(7,637)
Investing activities:
Purchases of fixed assets	0	(13)
Maturities of short-term investments	3,500	12,000
Purchases of short-term investments	(9,821)	(2,960)
Net cash provided by (used in) investing activities	(6,321)	9,027
Financing activities:
Repayment of term loans	(556)	0
Proceeds from exercise of common stock options and prefunded warrants	1	0
Proceeds from issuance of common stock, net of issuance costs	14,787	212
Net cash provided by financing activities	14,232	212
Net increase in cash and cash equivalents	633	1,602
Cash and cash equivalents at beginning of period	14,875	8,708
Cash and cash equivalents at end of period	15,508	10,310
Supplemental disclosure of cash flow information
Interest paid	655	589
Operating lease liabilities arising from obtaining right-of-use assets	186	0
Supplemental disclosure of non-cash investing and financing activities:
Accrued issuance costs	$ 109	$ 170

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (8,834)	$ (10,014)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Description of Business Locust Walk Acquisition Corp. ("LWAC”) was initially formed on October 2, 2020 as a Delaware corporation formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business transaction with one or more operating businesses. On May 26, 2021, LWAC entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Locust Walk Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of LWAC (“Merger Sub”), and eFFECTOR Therapeutics, Inc., a Delaware corporation (“ Old eFFECTOR”). Pursuant to the terms of the Merger Agreement, a business combination between LWAC and Old eFFECTOR was effected through the merger of the Merger Sub with and into Old eFFECTOR, with Old eFFECTOR becoming the surviving company and a wholly-owned subsidiary of LWAC with the name of eFFECTOR Therapeutics Operations, Inc. On August 25, 2021, and in connection with the closing of the business combination (the "Business Combination"), LWAC was renamed eFFECTOR Therapeutics, Inc. ("eFFECTOR" or the "Company"). All outstanding preferred shares of Old eFFECTOR converted into common shares of Old eFFECTOR on a 1:1 basis, which were then converted, along with all outstanding common shares of Old eFFECTOR, into common shares of the surviving eFFECTOR company through application of an exchange ratio of approximately 0.09657 . The Company is a clinical-stage biopharmaceutical company focused on pioneering the development of a new class of oncology drugs the Company refers to as selective translation regulator inhibitors ("STRIs"). The Company’s principal operations are in the United States, with its headquarters in Solana Beach, California. The Company has devoted substantially all of its resources to raising capital, identifying potential product candidates, establishing its intellectual property portfolio, conducting preclinical studies and clinical trials, establishing arrangements with third parties for the manufacture of its product candidates and related raw materials, and providing general and administrative support for these operations. The Company has not generated revenues from its principal operations, other than from licensing and grant revenue, through March 31, 2024. Reverse Stock Split On January 9, 2024, the Company filed a Certificate of Amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended to date, with the Secretary of State of the State of Delaware to effect a reverse stock split of the Company’s common stock, par value $ 0.0001 at a ratio of 1-for-25 (the “Reverse Stock Split”), as authorized at the Company’s 2023 annual meeting of stockholders held on June 22, 2023. The Company effected the Reverse Stock Split on January 12, 2024. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise were entitled to a fractional share of common stock were entitled to receive a proportional cash payment. The number of shares of common stock that the Company is authorized to issue was proportionally reduced from 1,000,000,000 shares to 40,000,000 shares and the par value of its common stock remains unchanged at $ 0.0001 per share. The Company has retroactively restated the share and per share amounts in the consolidated financial statements as of December 31, 2023 and for the three months ended March 31, 2024 and 2023. Proportionate adjustments were made to the per share exercise price and number of shares of common stock issuable under all outstanding stock options and warrants. In addition, proportionate adjustments have been made to the number of shares of common stock reserved for the Company’s equity incentive compensation plans. The consolidated statements of stockholders’ equity (deficit) and balance sheets reflect the impact of the Reverse Stock Split by reclassifying from “common stock” to “additional paid-in capital” in an amount equal to the par value of the decreased shares resulting from the Reverse Stock Split. Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of March 31, 2024 and for the three months ended March 31, 2024 and 2023 have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three months ended March 31, 2024 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2023 has been derived from the audited financial statements at that date but does not include all the disclosures required by GAAP for complete financial statements. Because all of the disclosures required by GAAP for complete financial statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2023 included in its Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 26, 2024. Liquidity The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2). The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the years ended December 31, 2021 and December 31, 2020 when net income was realized as a result of a gain in fair value recognized associated with the earn-out liability and revenue in connection with the Research Collaboration and License Agreement with Pfizer, respectively. The Company has an accumulated deficit of $ 188.2 million at March 31, 2024. For the three months ended March 31, 2024, the Company used $ 7.3 million in cash for operations. At March 31, 2024, the Company had cash and cash equivalents and short-term investments of $ 25.4 million. The Company anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. Management has prepared cash flow forecasts which indicate that based on the Company’s expected operating losses and negative cash flows, there is substantial doubt about the Company’s ability to continue as a going concern within twelve months from the date that these financial statements for the three months ended March 31, 2024 are issued. The principal payments due under the Oxford Loans (as defined below), and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed above and the assessment that the material adverse change clause under the Oxford Loans is not within the Company’s control. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements. The Company’s ability to continue as a going concern is dependent upon its ability to receive additional capital. Management intends to raise additional capital through equity offerings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. Additionally, the Company may receive additional milestone payments from the Research Collaboration and License Agreement with Pfizer (described in Note 10), through the issuance of common stock under the equity purchase agreement with Lincoln Park Capital Fund, LLC (described in Note 8) or through the issuance of common stock under the at-the-market offering program (described in Note 8) with Cantor Fitzgerald & Co. However, the Company may not be able to secure additional financing in a timely manner or on favorable terms, if at all, and may not receive any milestone payments. Without additional capital, the Company may be forced to delay, scale back or eliminate some of its research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations, or may be required to pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders .

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Research and Development Costs Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred. Clinical Trial Accruals and Preclinical Studies The Company records expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates based on the underlying contracts, correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted, and amounts invoiced or paid to date. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates. Public and Private Placement Warrants Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their initial public offering in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying consolidated statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model. Stock-Based Compensation Expense Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach. The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk-free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant. Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company presents comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss. Cash, Cash Equivalents and Short-term Investments Cash and Cash Equivalents The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase. Short-term Investments Short-term investments consist of U.S. Treasury securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified all of its available-for-sale securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. Amortization and accretion of any purchase premiums or discounts is included in interest income in the consolidated statements of operations and comprehensive loss. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on its preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. For the three months ended March 31, 2024, all pre-funded warrants that were issued during the January 2024 Registered Direct Offering (as defined below) with an exercise price of $ 0.001 , regardless of whether they were exercised as of March 31, 2024, were considered outstanding in the calculation of basic and diluted net loss per share (See Note 7 for details about pre-funded warrants) . Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares): For the Three Months Ended March 31, 2024 2023 Common stock warrants 2,257,426 — Placement agent warrants 158,017 — Public warrants 233,332 233,332 Private placement warrants 7,266 7,266 Earn-Out Shares — 200,000 Unvested sponsor shares 12,000 12,000 Stock options outstanding 694,764 473,900 Total 3,362,805 926,498

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2: Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e. supported by little or no market activity). The Company’s cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The Company estimates the fair value of its warrant liabilities at the time of issuance and subsequent remeasurement using the Black-Scholes option pricing model at each reporting date, if required, based on the following inputs: the risk-free interest rates; the expected dividend rates; the remaining contractual life of the warrants; the fair value of the underlying stock; and the expected volatility of the price of the underlying stock. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions as well as the fair value of the Company’s stock on the reporting date can have a significant impact on the fair value of the warrant liability. The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of March 31, 2024 and December 31, 2023 (in thousands): Fair Value Measurements Using March 31, Quoted Prices Significant Significant 2024 Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 6,048 $ 6,048 $ — $ — U.S. Treasury securities 9,460 — 9,460 — Short-term investments: U.S. Treasury securities 9,875 — 9,875 — Total assets $ 25,383 $ 6,048 $ 19,335 $ — Liabilities Private placement warrant liability $ 40 $ — $ — $ 40 Total liabilities $ 40 $ — $ — $ 40 Fair Value Measurements Using December 31, Quoted Prices Significant Significant 2023 Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 10,887 $ 10,887 $ — $ — U.S. Treasury securities 3,988 — 3,988 — Short-term investments: U.S. Treasury securities 3,495 — 3,495 — Total assets $ 18,370 $ 10,887 $ 7,483 $ — Liabilities Private placement warrant liability $ 40 $ — $ — $ 40 Total liabilities $ 40 $ — $ — $ 40 Cash Equivalents and Short-Term Investments Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase and short-term investments consisted of U.S. Treasury securities with an original maturity of more than three months at the date of purchase. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bids and/or offers. Investments are classified as Level 1 within the fair value hierarchy if their quoted prices are available in active markets for identical securities. Investments in money market funds of $ 6.0 million and $ 10.9 million as of March 31, 2024 and December 31, 2023, respectively, were classified as Level 1 instruments and were included in cash and cash equivalents. Investments in marketable securities are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported upon utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations. The marketable securities of $ 19.3 million as of March 31, 2024 were classified as Level 2 instruments, $ 9.5 million of which is included in cash and cash equivalents and $ 9.9 million of which is included in short-term investments. The marketable securities of $ 7.5 million as of December 31, 2023 were classified as Level 2 instruments, $ 4.0 million of which is included in cash and cash equivalents and $ 3.5 million of which is included in short-term investments. Accrued interest receivable related to short-term investments was $ 17,000 and $ 52,000 as of March 31, 2024 and December 31, 2023, respectively, and included as part of prepaid expenses and other current assets in the condensed balance sheets. The following tables summarize the Company’s short-term investments accounted for as available-for-sale securities as of March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value U.S. Treasury securities 1 year or less $ 9,875 $ — $ — $ 9,875 $ 9,875 $ — $ — $ 9,875 December 31, 2023 Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value U.S. Treasury securities 1 year or less $ 3,495 $ — $ — $ 3,495 $ 3,495 $ — $ — $ 3,495 Private Placement Warrant Liability In connection with the Business Combination, the Company assumed the public and private placement warrants described in Note 2. The private placement warrants are precluded from equity treatment and are recorded as liabilities as they are not considered indexed to the Company's common stock. The private placement warrant liability is measured at fair value, using a combination of observable and unobservable inputs. The change in fair value of the private placement warrant liability is recorded in other income (expense) on the statement of operations and comprehensive loss. The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of March 31, 2024 and December 31, 2023: March 31, December 31, Common stock price $ 14.39 $ 11.69 Expected volatility 125.0 % 125.0 % Risk-free interest rate 4.5 % 4.1 % Expected term (in years) 2.4 2.7 Expected dividend yield — — The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the three months ended March 31, 2024 (in thousands): Private Placement Warrant Liability Balance at December 31, 2023 $ 40 Change in fair value — Balance at March 31, 2024 $ 40

Property and Equipment , net

Property and Equipment , net	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment , net	4. Property and Equipment, net Property and equipment, net consists of the following (in thousands): March 31, December 31, Lab equipment $ 108 $ 30 Computer and office equipment 154 154 Furniture and fixtures 78 78 Leasehold improvements 188 188 Construction in process 14 14 542 464 Less accumulated depreciation and amortization ( 352 ) ( 324 ) $ 190 $ 140 The Company recorded depreciation and amortization expense of approximately $ 28,000 for each of the three months ended March 31, 2024 and 2023 .

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consist of the following (in thousands): March 31, December 31, Employee compensation $ 978 $ 1,587 Research and development 2,461 1,036 Professional and outside services 131 75 Interest 217 223 $ 3,787 $ 2,921

Term Loans

Term Loans	3 Months Ended
	Mar. 31, 2024
Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]
Term Loans	6. Term Loans Oxford Term Loans In March 2021, Old eFFECTOR entered into a Loan and Security Agreement (“Oxford LSA”) with Oxford Finance LLC (“Oxford”), pursuant to which the Company may borrow up to $ 30.0 million, issuable in two separate tranches of $ 20.0 million (“Term A Loans”) and $ 10.0 million (“Term B Loans”), collectively referred to as the Oxford Loans. In March 2021, the Company borrowed $ 20.0 million of the Term A Loans. The Company is required to make a final payment equal to 5.5 % of the Term A Loans at maturity, which has been recorded as a debt discount for the Term A Loans and is being amortized over the term of the debt arrangements. In connection with the Oxford LSA, the Company issued warrants to purchase a total of 1,503 shares of Series C Preferred Stock at an exercise price of $ 133.25 per share. On February 22, 2022, the Company entered into an amendment to the Oxford LSA whereby the interest only period for the Term A Loans ended on March 1, 2024 . In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027. Additionally, Term B Loans would have become available to the Company after January 1, 2023 upon achievement of certain clinical development milestones, until the earlier of (i) June 30, 2023 , (ii) 45 days after the achievement of certain clinical development milestones, and (iii) the occurrence of an event of default. As the Company did not achieve the clinical development milestones by June 30, 2023, it no longer has access to the additional $ 10.0 million under the Term B Loans. The amendment was accounted for as a debt modification as the modified debt was not substantially different from the original debt and the cash flows were not significantly changed . The Oxford Loans carry a variable interest rate equal to the greater of (i) 7.7 % and (ii) the sum of the prime rate plus 4.45 %. The Company has the option to prepay all, but not less than all, of the borrowed amounts, and there is no prepayment fee for a prepayment made after the third anniversary of the effective date of the Oxford LSA and prior to the maturity date. The Company’s obligations under the Oxford LSA are secured by a first priority security interest in substantially all of its current and future assets, other than its owned intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on its ability to encumber intellectual property assets without consent. The Company recorded a debt discount of $ 1.6 million for the estimated fair value of warrants, debt issuance costs, and final payment to be made, which is being amortized to interest expense over the term of the loan using the effective-interest method. As of March 31, 2024 , the Company had $ 19.4 million of outstanding principal under the Term A Loans of which $ 18.9 million is reflected on the balance sheet net of debt discounts. As of December 31, 2023 , the Company had $ 20.0 million of outstanding principal under the Term A Loans of which $ 19.4 million is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the Oxford Term A Loans, totaled $ 0.7 million for each of the three months ended March 31, 2024 and 2023. The Company is in compliance with all covenants under the Oxford LSA as of March 31, 2024. The Term A Loans include customary events of default, including instances of a material adverse change in our operations, that may require prepayment of the outstanding Term A Loans. The principal payments due under the Oxford Loans, and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed in the Liquidity section of Note 1. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements. Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of March 31, 2024 (in thousands): As of March 31, 2024 Remainder of 2024 $ 5,000 2025 6,667 2026 6,667 2027 1,110 Required future principal payments $ 19,444 Unamortized debt discount ( 528 ) Current term loans, net as of March 31, 2024 $ 18,916

Warrants

Warrants	3 Months Ended
	Mar. 31, 2024
Warrants and Rights Note Disclosure [Abstract]
Warrants	7. Warrants Assumed Public Warrants and Private Placement Warrants Following the consummation of the Business Combination, holders of the public warrants and private placement warrants are entitled to acquire common stock of the Company. The warrants became exercisable on January 12, 2022, which is 12 months from the closing of the LWAC's initial public offering. Each warrant entitles the registered holder to purchase one share of common stock at an exercise price of $ 287.50 per share. The public warrants and private placement warrants will expire on August 25, 2026 , which is five years after the completion of the Business Combination. Once the public warrants and private placement warrants became exercisable, the Company has the right to redeem the outstanding warrants in whole and not in part at a price of $ 0.25 per warrant upon a minimum of 30 days’ prior written notice of redemption, if and only if the last sale price of the common stock equals or exceeds $ 450.00 per share for any 20 trading days within a 30 -trading day period ending on the third trading day prior to the date on which the Company sends the notice of redemption to the warrant holders. The private placement warrants are identical to the public warrants except that, so long as they are held by the sponsor or its permitted transferees: (i) they will not be redeemable by the Company; (ii) they may be exercised by the holders on a cashless basis; and (iii) they are subject to registration rights. Private placement warrants are liability-classified (See Note 3) and the public warrants are equity-classified. The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023: March 31, December 31, Exercise Price Expiration Date Public warrants 233,332 233,332 $ 287.50 August 24, 2026 Private placement warrants 7,266 7,266 $ 287.50 August 24, 2026 Warrants - Registered Direct Offerings In May 2023, the Company completed a registered direct offering (“May 2023 Registered Direct Offering”) which included the issuance of 270,015 shares of common stock in the form of pre-funded warrants with a purchase price of $ 16.35 per share and an exercise price of $ 0.025 (the “May 2023 Pre-Funded Warrants”). The May 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 458,015 shares of common stock (the “May 2023 Common Stock Warrants”) with an exercise price of $ 13.25 per share. The May 2023 Common Stock Warrants will expire on November 30, 2028 , which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 32,060 shares of common stock ("May 2023 Placement Agent Warrants") with an exercise price of $ 20.47 per share. The May 2023 Placement Agent Warrants will expire on May 26, 2028 , which is five years following the commencement of sales in the May 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the May 2023 Registered Direct Offering. In June 2023, the Company completed a registered direct offering (“June 2023 Registered Direct Offering”) which included the issuance of 72,578 shares of common stock in the form of pre-funded warrants with a purchase price of $ 28.10 per share and an exercise price of $ 0.025 (the “June 2023 Pre-Funded Warrants”). The June 2023 Pre-Funded Warrants were immediately exercised. Additionally, in a concurrent private placement, the Company issued warrants to purchase up to 310,577 shares of common stock (the “June 2023 Common Stock Warrants”) with an exercise price of $ 25.00 per share. The June 2023 Common Stock Warrants will expire on December 8, 2028 , which is five and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 21,739 shares of common stock ("June 2023 Placement Agent Warrants") with an exercise price of $ 35.1575 per share. The June 2023 Placement Agent Warrants will expire on June 6, 2028 , which is five years following the commencement of sales in the June 2023 Registered Direct Offering. See Note 8 for additional detail surrounding the June 2023 Registered Direct Offering. In January 2024, the Company completed a registered direct offering (“January 2024 Registered Direct Offering”) which included the issuance of 1,150,834 shares of common stock in the form of pre-funded warrants with a purchase price of $ 10.074 per share and an exercise price of $ 0.001 (the “January 2024 Pre-Funded Warrants”), of which 497,834 were exercised as of March 31, 2024. Additionally, the Company concurrently issued warrants to purchase up to 1,488,834 shares of common stock (the “January 2024 Common Stock Warrants”) with an exercise price of $ 9.95 per share. The January 2024 Common Stock Warrants will expire on July 29, 2027 , which is three and one-half years from the issuance date. Further, the Company issued warrants to designees of the placement agent to purchase up to 104,218 shares of common stock ("January 2024 Placement Agent Warrants") with an exercise price of $ 12.5938 per share. The January 2024 Placement Agent Warrants will expire on July 29, 2027 , which is three and one-half years from the issuance date. See Note 8 for additional detail surrounding the January 2024 Registered Direct Offering. The common stock warrants, placement agent warrants and pre-funded warrants are equity-classified. The following table summarizes the number of outstanding common stock warrants, placement agent warrants and pre-funded warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023: March 31, December 31, Exercise Price Expiration Date May 2023 Common Stock Warrants 458,015 458,015 $ 13.25 November 30, 2028 May 2023 Placement Agent Warrants 32,060 32,060 $ 20.47 May 26, 2028 June 2023 Common Stock Warrants 310,577 310,577 $ 25.00 December 8, 2028 June 2023 Placement Agent Warrants 21,739 21,739 $ 35.1575 June 6, 2028 January 2024 Pre-funded Warrants 653,000 — $ 0.001 N/A January 2024 Common Stock Warrants 1,488,834 — $ 9.95 July 29, 2027 January 2024 Placement Agent Warrants 104,218 — $ 12.5938 July 29, 2027

Preferred Stock and Stockholder

Preferred Stock and Stockholders' Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Preferred Stock and Stockholders' Equity	8. Preferred Stock and Stockholders’ Equity (Deficit) Purchase Agreement On January 24, 2022, the Company entered into an equity purchase agreement (the “Purchase Agreement”) and a registration rights agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park”) which provides for the sale to Lincoln Park up to $ 50.0 million of shares (the “Purchase Shares”) of the Company's common stock over the thirty-six ( 36 ) month term of the Purchase Agreement. In connection with the Purchase Agreement, Lincoln Park made an initial purchase of $ 3.0 million of shares of common stock, which equated to 22,304 shares of common stock, and the Company issued 5,717 shares of common stock to Lincoln Park as a commitment fee in connection with entering into the Purchase Agreement. The Company recognized $ 0.8 million of other expense relating to the commitment fee share issuance. As of March 31, 2024 , a total of 1,200 shares of common stock have been sold in addition to the upfront amount, with such shares sold during the three months ended June 30, 2022. There were no purchases under the Purchase Agreement during the three months ended March 31, 2024 and 2023. Under the Purchase Agreement, the Company has sole discretion, subject to certain conditions, on any business day selected by the Company to require Lincoln Park to purchase up to 1,200 shares of common stock (the “Fully Adjusted Regular Purchase Share Limit”) at the Purchase Price (as defined below) per purchase notice (each such purchase, a “Regular Purchase”). The Fully Adjusted Regular Purchase Share Limit may be increased as follows: to up to 2,000 shares if the closing price is not below $125.00, and up to 3,000 shares if the closing price is not below $250.00. Lincoln Park’s committed obligation under each Regular Purchase is capped at $ 500,000 , unless the Parties agree otherwise. The purchase price for Regular Purchases (the “Purchase Price”) shall be equal to the lesser of: (i) the lowest sale price of the common shares during the Purchase Date (as defined in the Purchase Agreement), or (ii) the average of the three (3) lowest closing sale prices of the common shares during the ten (10) business days prior to the Purchase Date. In addition to Regular Purchases and subject to certain conditions and limitations, the Company in its sole discretion may require Lincoln Park on each Purchase Date to purchase on the following business day up to the lesser of (i) three (3) times the number of shares purchased pursuant to such Regular Purchase or (ii) 25 % of the trading volume on the Accelerated Purchase Date (as defined in the Purchase Agreement) (the “Accelerated Purchase”) (unless the Parties agree otherwise) at a purchase price equal to the lesser of 97 % of (i) the closing sale price on the Accelerated Purchase Date, or (ii) the Accelerated Purchase Date’s volume weighted average price (the “Accelerated Purchase Price”). The Company has the sole right to set a minimum price threshold for each Accelerated Purchase in the notice provided with respect to such Accelerated Purchase and under certain circumstances and in accordance with the Purchase Agreement the Company may direct multiple Accelerated Purchases in a day. The aggregate number of shares that the Company can sell to Lincoln Park under the Purchase Agreement may not exceed 325,357 shares of the Common Shares (which is equal to approximately 19.99 % of the shares of the Common Shares outstanding immediately prior to the execution of the Purchase Agreement) (the “Exchange Cap”), unless (i) shareholder approval is obtained to issue Purchase Shares above the Exchange Cap, in which the Exchange Cap will no longer apply, or (ii) the average price of all applicable sales of Common Shares to Lincoln Park under the Purchase Agreement equals or exceeds $ 160.50 per share; provided that at no time may Lincoln Park (together with its affiliates) beneficially own more than 4.99 % of the Company’s issued and outstanding Common Shares. The Purchase Agreement contains customary representations, warranties, covenants, closing conditions, indemnification and termination provisions. The Purchase Agreement may be terminated by the Company at any time, at its sole discretion, without any cost or penalty, by giving one business day notice to Lincoln Park. Further, Lincoln Park has covenanted not to engage in any direct or indirect short selling or hedging of the Common Shares. There are no limitations on the use of proceeds, financial or business covenants, restrictions on future financings (other than restrictions on the Company’s ability to enter into a similar type of agreement or Equity Line of Credit during the Term, excluding an At-The-Market transaction with a registered broker-dealer), rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement. At-the-Market Offering Program In September 2022, the Company entered into a Controlled Equity Offering Sales Agreement (the "Cantor Sales Agreement") with Cantor Fitzgerald & Co ("Cantor"), under which the Company could have sold, from time to time, shares of the Company’s common stock having an aggregate offering price of up to $ 50.0 million in “at the market” offerings (the "ATM Offering Program") through Cantor. In August 2023, the Company supplemented its prospectus, dated September 9, 2022 (the “Prospectus Supplement”), to increase the aggregate offering amount under the ATM Offering Program to $ 50.0 million as the Company was no longer subject to General Instruction I.B.6. of Form S-3, which limited the amounts that the Company could sell under the ATM Offering Program. In April 2024, the Company supplemented the prospectus to reduce the aggregate offering amount under the ATM Offering Program to approximately $ 6.8 million, which was less than one-third of our public float, as calculated on the day of filing. Sales of the shares of common stock were made at prevailing market prices at the time of sale, or as otherwise agreed with Cantor. Cantor received a commission from the Company of up to 3.0 % of the gross proceeds of any shares of common stock sold under the Sales Agreement. During the three months ended March 31, 2024 , the Company sold an aggregate of 83,948 shares of common stock at a weighted-average price of $ 11.07 per share for gross proceeds of approximately $ 0.9 million under the ATM Offering Program. Offering costs, including commissions, of approximately $ 0.1 million were recorded as an offset to gross proceeds within additional paid-in capital. Registered Direct Offerings The May 2023 Registered Direct Offering included the issuance and sale of an aggregate of 188,000 shares of the Company’s common stock at a purchase price of $ 16.375 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the May 2023 Pre-Funded Warrants, which were immediately exercised, and the May 2023 Common Stock Warrants. The Company received gross proceeds from the May 2023 Registered Direct Offering of $ 7.5 million with net proceeds of approximately $ 6.7 million after deducting $ 0.8 million in commissions and other transaction costs. In connection with the May 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0 % of the gross proceeds received by the Company from the offering and a management fee equal to 1.0 % of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $ 75,000 for non-accountable expenses and $ 15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the May 2023 Placement Agent Warrants, equal to 7.0 % of the aggregate number of shares of common stock and pre-funded warrants placed in the offering. The June 2023 Registered Direct Offering included the issuance and sale of an aggregate of 238,000 shares of the Company’s common stock at a purchase price of $ 28.125 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the June 2023 Pre-Funded Warrants, which were immediately exercised, and the June 2023 Common Stock Warrants. The Company received gross proceeds from the June 2023 Registered Direct Offering of $ 8.7 million with net proceeds of approximately $ 7.8 million after deducting $ 0.9 million in commissions and other transaction costs. In connection with the June 2023 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0 % of the gross proceeds received by the Company from the offering and a management fee equal to 1.0 % of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $ 50,000 for non-accountable expenses and $ 15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the June 2023 Placement Agent Warrants, equal to 7.0 % of the aggregate number of shares of common stock and pre-funded warrants placed in the offering. The January 2024 Registered Direct Offering included the issuance and sale of an aggregate of 338,000 shares of the Company’s common stock at a purchase price of $ 10.075 per share in a registered direct offering priced at-the-market under Nasdaq rules. In addition, the offering included the issuance of the January 2024 Pre-Funded Warrants and the January 2024 Common Stock Warrants. The Company received gross proceeds from the January 2024 Registered Direct Offering of $ 15.0 million with net proceeds of approximately $ 13.6 million after deducting $ 1.4 million in commissions and other transaction costs. In connection with the January 2024 Registered Direct Offering, the Company paid H.C. Wainwright & Co., LLC, as exclusive placement agent, an aggregate cash fee equal to 7.0 % of the gross proceeds received by the Company from the offering and a management fee equal to 1.0 % of the gross proceeds received by the Company from the offering. The Company also paid the placement agent $ 25,000 for non-accountable expenses, $ 50,000 for fees and expenses of legal counsel and other out-of-pocket expenses, and $ 15,950 for clearing fees. Additionally, the Company issued designees of the placement agent the January 2024 Placement Agent Warrants, equal to 7.0 % of the aggregate number of shares of common stock and pre-funded warrants placed in the offering. Preferred Stock Upon closing of the Business Combination transaction, pursuant to the terms of the Amended and Restated Certificate of Incorporation, 100,000,000 shares of preferred stock with a par value of $ 0.0001 per share were authorized. eFFECTOR's Board of Directors (the "Board of Directors") has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, voting, and other rights, preferences and privileges of the shares. There were no issued and outstanding shares of preferred stock immediately after the closing of the Business Combination and no preferred stock has been issued as of March 31, 2024. Sponsor Shares In connection with the closing of the Business Combination, the LWAC sponsor received 162,250 shares of eFFECTOR common stock, of which 12,000 shares were subject to vesting if, on or prior to August 25, 2024, the price of shares of common stock equals or exceeds $ 375.00 per share for a period of at least 20 trading days out of 30 consecutive trading days ending on the trading day immediately prior to the date of determination (the "Sponsor Shares"). The 12,000 Sponsor Shares subject to vesting meet the criteria for equity classification, but are not considered outstanding from an accounting perspective. These shares are considered issued but not outstanding as of March 31, 2024 and December 31, 2023, and have been excluded from outstanding shares in the calculation of loss per share for the three months ended March 31, 2024 and 2023. Employee Stock Purchase Plan The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85 % of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. An aggregate of 35,200 shares were initially reserved and available for issuance under the ESPP. The ESPP provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, by 1.0 % of the outstanding number of shares of common stock on the immediately preceding December 31, or such lesser amount as determined by our Board of Directors; provided that the total number of shares of common stock that become available for issuance under the ESPP will never exceed 600,000 . If our capital structure changes because of a stock dividend, stock split or similar event, the number of shares that can be issued under the ESPP will be appropriately adjusted. As of March 31, 2024 , 89,090 shares were reserved for future issuance under the ESPP. There were no shares of common stock issued under the ESPP during the three months ended March 31, 2024 and 2023. 2013 Equity Incentive Plan Prior to the Business Combination, Old eFFECTOR maintained its 2013 Equity Incentive Plan (the “2013 Plan”), under which Old eFFECTOR granted incentive stock options, restricted stock awards, and other stock-based awards to employees, directors, and non-employee consultants. Upon the completion of the Business Combination, the Company ceased granting awards under the 2013 Plan and, as described below, all awards under the 2013 Plan were converted into awards under the 2021 Plan with the same terms and conditions. In connection with the completion of the Business Combination and the adoption of the 2021 Plan, no further awards will be granted under the 2013 Plan. As of March 31, 2024 , the number of shares reserved and options outstanding under the 2013 Plan was 130,617 . 2021 Equity Incentive Plan In connection with the consummation of the Business Combination on August 25, 2021, the Board of Directors approved the adoption of the 2021 Equity Incentive Plan (the “2021 Plan”). As of March 31, 2024 , 596,440 shares of common stock are authorized for issuance pursuant to awards under the 2021 Plan, inclusive of any shares of common stock subject to stock options, restricted stock awards or other awards that were assumed in the Business Combination. As of March 31, 2024 , 607,306 options to purchase common shares have been awarded and 32,293 shares remain available for issuance under the 2021 Plan. The 2021 Plan permits the granting of incentive stock options, restricted stock awards, other stock-based award or other cash-based awards to employees, directors, and non-employee consultants. Options granted under the 2021 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant, or in the case of certain non-statutory options, ten years from the date of grant. The exercise price of each option shall be determined by the Board of Directors based on the fair market value of the Company’s stock on the date of the option grant, defined as the closing sales price of the Company's common stock. In the case of incentive stock options, the exercise price shall not be less than 100 % of the fair market value of the Company’s common stock at the time the option is granted. For holders of more than 10 % of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110 % of the fair market value of the Company’s stock at the date of grant and for a term not to exceed five years. A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years): Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2023 480,875 $ 51.67 7.3 $ — Granted 231,800 11.32 9.9 Cancelled or forfeited ( 17,911 ) 13.53 3.9 Outstanding at March 31, 2024 694,764 $ 39.19 7.9 $ 1,039 Vested and exercisable at March 31, 2024 325,122 $ 56.29 6.3 $ 151 For the three months ended March 31, 2024 the total fair value of vested options was $ 1.0 million . The weighted-average grant date fair value of employee and non-employee option grants during the three months ended March 31, 2024 was $ 8.27 per share. Stock-Based Compensation Expense The Company recognized stock-based compensation expense specifically related to stock options of $ 1.0 million and $ 1.2 million for three months ended March 31, 2024 and 2023, respectively. The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows: Three Months Ended March 31, 2024 2023 Risk-free interest rate 4.3 % 3.6 % - 4.1 % Expected volatility 84 % - 85 % 84 % Expected term (in years) 5.3 - 6.0 5.3 - 6.1 Expected dividend yield 0 % 0 % Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the weighted average of the time-to-vesting and the contractual life of the options. Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends. Forfeitures . The Company reduces stock-based compensation expense for actual forfeitures during the period in which they occur. As of March 31, 2024 , the unrecognized compensation cost related to outstanding employee options was $ 5.6 million and is expected to be recognized as expense over approximately 2.8 years. Unrecognized compensation cost related to outstanding nonemployee options was $ 0.6 million as of March 31, 2024, and is expected to be recognized as expense over approximately 1.0 year. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following as of March 31, 2024 and December 31, 2023: March 31, December 31, Stock options issued and outstanding 694,764 480,875 Public warrants issued and outstanding 233,332 233,332 Private placement warrants issued and outstanding 7,266 7,266 Common stock warrants issued and outstanding 2,257,426 768,592 Placement agent warrants issued and outstanding 158,017 53,799 Pre-funded warrants 653,000 — Unvested sponsor shares 12,000 12,000 Authorized for future stock awards or option grants 32,293 96,449 Authorized for future issuances under the ESPP 89,090 59,144 Total 4,137,188 1,711,457

License Agreements

License Agreements	3 Months Ended
	Mar. 31, 2024
License Agreement Disclosure [Abstract]
License Agreement	9. License Agreements In May 2013, the Company entered into an agreement with the Regents of the University of California (“UCSF”) which provides the Company with an exclusive license to UCSF’s patent rights in certain inventions (the “UCSF Translational Profiling Patent Rights”) relating to translational profiling laboratory techniques initially developed at UCSF. Under the agreement, the Company is permitted to research, develop, make and sell products that it discovers and develops utilizing the UCSF Translational Profiling Patent Rights, which the Company refers to as licensed products, and use certain licensed processes utilizing the UCSF Translational Profiling Patent Rights and to sublicense such licensed products and processes. In July 2021, the Company entered into an amendment to the license agreement to confirm the impact of the Business Combination on the license agreement, including clarifying that in connection with the closing of the Business Combination, the Company would pay UCSF a one-time cash payment of approximately $ 1.0 million. The $ 1.0 million payment was made to UCSF in August 2021 in connection with the close of the Business Combination. The Company is also required to make cash milestone payments to UCSF upon the completion of certain clinical and regulatory milestones for the licensed products. No milestone events occurred during the three months ended March 31, 2024 and March 31, 2023. The aggregate remaining potential milestone payments are approximately $ 375,000 . The Company pays an annual minimum royalty of $ 15,000 to UCSF. All license related fees are recorded as research and development expense.

Research Collaboration and Lice

Research Collaboration and License Agreement	3 Months Ended
	Mar. 31, 2024
Research and Development [Abstract]
Research Collaboration and License Agreement	10. Research Collaboration and License Agreement In December 2019, the Company entered into a Research Collaboration and License Agreement (the “Pfizer Agreement”) with Pfizer to research and develop small molecules that target eIF4E. Under the Pfizer Agreement, the Company was responsible for initial research in collaboration with Pfizer, and Pfizer is responsible for all further development of the program, including submission of an investigational new drug application and conducting all clinical development and commercialization activities. Pfizer is obligated to use commercially reasonable efforts to develop and seek regulatory approval for a licensed product, and commercialize a licensed product where Pfizer has received regulatory approval, in the United States and certain other countries. In the event the Company exercises its co-funding and co-promotion option, a joint steering committee will oversee the development plan and budget of the co-developed product, and the Company will have the responsibility to conduct a portion of product marketing presentations to healthcare providers. Pursuant to the Pfizer Agreement, the Company received an upfront, one-time, non-refundable, non-creditable payment of $ 15 million from Pfizer. Pfizer was obligated to reimburse the Company for costs incurred for research performed, up to a specified cap in the low double-digit millions. Upon the achievement of specified early development and regulatory milestones, Pfizer will be obligated to pay the Company up to $ 80 million in the aggregate. For other non-early stage development milestones Pfizer’s payment obligations to the Company depends upon whether the Company has exercised its co-funding and co-promotion option: 1) if it does not exercise the option, non-early stage development payments may total up to $ 165 million in aggregate, and 2) if it does exercise the option, non-early stage development payments may total up to $ 70 million in aggregate. Upon the achievement of specified sales milestones, Pfizer is also obligated to make tiered milestone payments of up to $ 235 million in aggregate. On a product-by-product basis, Pfizer will also be required to pay the Company high single-digit percentage royalties on annual net sales of each licensed product. If the Company exercises its co-promotion and co-funding option, royalty payments will exclude sales in the United States and the Company will share with Pfizer profits from sale of the relevant licensed product in the United States. The initial transaction price of $ 27.0 million was allocated to the two performance obligations on a relative standalone value basis, with $ 25.6 million allocated to the license and $ 1.4 million allocated to the research activities , which were completed in 2020. The value attributable to the license was recognized upon delivery of the license to Pfizer and the value attributable to the research activities was recognized pro-rata based on the actual costs incurred by the Company compared to the total estimated costs of the research activities from the time of execution to the end of the research program. There was no revenue recorded in connection with this agreement for the three months ended March 31, 2024 and 2023 because all development and sales milestones (variable consideration) were fully constrained.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies Leases In September 2021, the Company entered a non-cancelable three-year lease for certain office space in Solana Beach, California, with an option to renew for an additional three-year term. In January 2024, the Company executed a three-year extension to the lease with a new expiration date of October 31, 2027. The initial term of the lease started on November 1, 2021, and is serving as the Company's headquarters. Rent expense under this lease was $ 18,000 and $ 16,000 for the three months ended March 31, 2024 and 2023, respectively. During the three months ended March 31, 2024 and 2023, the Company paid $ 19,000 and $ 14,000 in lease payments, respectively, which were included in operating activities in the statements of cash flows. The following table summarizes supplemental balance sheet information related to leases as of March 31, 2024 and December 31, 2023 (in thousands): March 31, December 31, Assets: Operating lease right-of-use assets $ 225 $ 53 Total right-of-use assets 225 53 Liabilities Operating lease liabilities, current 53 60 Operating lease liabilities, non-current 179 — Total operating lease liabilities $ 232 $ 60 As of March 31, 2024, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate): Remainder of 2024 $ 56 2025 77 2026 79 2027 68 Total remaining lease payments 280 Less: imputed interest ( 48 ) Total operating lease liabilities 232 Less: current portion ( 53 ) Long-term operating lease liabilities $ 179 Weighted-average remaining lease term ( in years ) 3.60 Weighted-average discount rate 11.5 %

Employee Benefits

Employee Benefits	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Employee Benefits	12. Employee Benefits The Company has a defined contribution 401(k) plan available to eligible employees. Under the terms of the plan, employees may make voluntary contributions as a percent of compensation, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain contributions to the 401(k) plan. Through March 31, 2024 , the Company made no matching contributions.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of March 31, 2024 and for the three months ended March 31, 2024 and 2023 have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three months ended March 31, 2024 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2023 has been derived from the audited financial statements at that date but does not include all the disclosures required by GAAP for complete financial statements. Because all of the disclosures required by GAAP for complete financial statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2023 included in its Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 26, 2024.
Liquidity	Liquidity The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2). The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the years ended December 31, 2021 and December 31, 2020 when net income was realized as a result of a gain in fair value recognized associated with the earn-out liability and revenue in connection with the Research Collaboration and License Agreement with Pfizer, respectively. The Company has an accumulated deficit of $ 188.2 million at March 31, 2024. For the three months ended March 31, 2024, the Company used $ 7.3 million in cash for operations. At March 31, 2024, the Company had cash and cash equivalents and short-term investments of $ 25.4 million. The Company anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. Management has prepared cash flow forecasts which indicate that based on the Company’s expected operating losses and negative cash flows, there is substantial doubt about the Company’s ability to continue as a going concern within twelve months from the date that these financial statements for the three months ended March 31, 2024 are issued. The principal payments due under the Oxford Loans (as defined below), and the related accrued final payment, have been classified as current liabilities as of March 31, 2024, due to the considerations discussed above and the assessment that the material adverse change clause under the Oxford Loans is not within the Company’s control. The Company has not been notified of an event of default by the lender as of the date of issuance of these financial statements. The Company’s ability to continue as a going concern is dependent upon its ability to receive additional capital. Management intends to raise additional capital through equity offerings or other capital sources, including potential additional collaborations, licenses and other similar arrangements. Additionally, the Company may receive additional milestone payments from the Research Collaboration and License Agreement with Pfizer (described in Note 10), through the issuance of common stock under the equity purchase agreement with Lincoln Park Capital Fund, LLC (described in Note 8) or through the issuance of common stock under the at-the-market offering program (described in Note 8) with Cantor Fitzgerald & Co. However, the Company may not be able to secure additional financing in a timely manner or on favorable terms, if at all, and may not receive any milestone payments. Without additional capital, the Company may be forced to delay, scale back or eliminate some of its research and development activities, or other operations and potentially delay product development in an effort to provide sufficient funds to continue its operations, or may be required to pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders .
Research and Development Costs	Research and Development Costs Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred.
Clinical Trial Accruals and Preclinical Studies	Clinical Trial Accruals and Preclinical Studies The Company records expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates based on the underlying contracts, correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted, and amounts invoiced or paid to date. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates.
Public and Private Placement Warrants	Public and Private Placement Warrants Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their initial public offering in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying consolidated statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model.
Stock-Based Compensation Expense	Stock-Based Compensation Expense Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach. The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk-free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The Company has limited historical stock option activity and therefore estimates the expected term of stock options granted using the simplified method, which represents the average of the contractual term of the stock option and its weighted-average vesting period. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant.
Comprehensive Loss	Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company presents comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.
Cash, Cash Equivalents and Short-term Investments	Cash, Cash Equivalents and Short-term Investments Cash and Cash Equivalents The Company considers all highly liquid investments with insignificant interest rate risk and an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist of money market funds and U.S. Treasury securities with an original maturity of less than three months at the date of purchase. Short-term Investments Short-term investments consist of U.S. Treasury securities, classified as available-for-sale securities and have maturities of greater than three months but less than one year. The Company has classified all of its available-for-sale securities as current assets on the balance sheets because these are considered highly liquid securities and are available for use in current operations. The Company carries these securities at fair value and reports unrealized gains and losses as a separate component of accumulated other comprehensive loss. Amortization and accretion of any purchase premiums or discounts is included in interest income in the consolidated statements of operations and comprehensive loss.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on its preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of common shares plus the potential dilutive effects of potential dilutive securities outstanding during the period. Potential dilutive securities are excluded from diluted earnings or loss per share if the effect of such inclusion is antidilutive. The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. For the three months ended March 31, 2024, all pre-funded warrants that were issued during the January 2024 Registered Direct Offering (as defined below) with an exercise price of $ 0.001 , regardless of whether they were exercised as of March 31, 2024, were considered outstanding in the calculation of basic and diluted net loss per share (See Note 7 for details about pre-funded warrants) . Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares): For the Three Months Ended March 31, 2024 2023 Common stock warrants 2,257,426 — Placement agent warrants 158,017 — Public warrants 233,332 233,332 Private placement warrants 7,266 7,266 Earn-Out Shares — 200,000 Unvested sponsor shares 12,000 12,000 Stock options outstanding 694,764 473,900 Total 3,362,805 926,498

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities	Potentially dilutive securities as of March 31, 2024 and 2023 are as follows (in common stock equivalent shares): For the Three Months Ended March 31, 2024 2023 Common stock warrants 2,257,426 — Placement agent warrants 158,017 — Public warrants 233,332 233,332 Private placement warrants 7,266 7,266 Earn-Out Shares — 200,000 Unvested sponsor shares 12,000 12,000 Stock options outstanding 694,764 473,900 Total 3,362,805 926,498

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Summary of assets and liabilities measured at fair value on a recurring basis	The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of March 31, 2024 and December 31, 2023 (in thousands): Fair Value Measurements Using March 31, Quoted Prices Significant Significant 2024 Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 6,048 $ 6,048 $ — $ — U.S. Treasury securities 9,460 — 9,460 — Short-term investments: U.S. Treasury securities 9,875 — 9,875 — Total assets $ 25,383 $ 6,048 $ 19,335 $ — Liabilities Private placement warrant liability $ 40 $ — $ — $ 40 Total liabilities $ 40 $ — $ — $ 40 Fair Value Measurements Using December 31, Quoted Prices Significant Significant 2023 Level 1 Level 2 Level 3 Assets Cash equivalents: Money market funds $ 10,887 $ 10,887 $ — $ — U.S. Treasury securities 3,988 — 3,988 — Short-term investments: U.S. Treasury securities 3,495 — 3,495 — Total assets $ 18,370 $ 10,887 $ 7,483 $ — Liabilities Private placement warrant liability $ 40 $ — $ — $ 40 Total liabilities $ 40 $ — $ — $ 40
Summary of Short term Investment	The following tables summarize the Company’s short-term investments accounted for as available-for-sale securities as of March 31, 2024 and December 31, 2023 (in thousands): March 31, 2024 Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value U.S. Treasury securities 1 year or less $ 9,875 $ — $ — $ 9,875 $ 9,875 $ — $ — $ 9,875 December 31, 2023 Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value U.S. Treasury securities 1 year or less $ 3,495 $ — $ — $ 3,495 $ 3,495 $ — $ — $ 3,495
Private Placement Warrants Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Summary of fair value measurements inputs	The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of March 31, 2024 and December 31, 2023: March 31, December 31, Common stock price $ 14.39 $ 11.69 Expected volatility 125.0 % 125.0 % Risk-free interest rate 4.5 % 4.1 % Expected term (in years) 2.4 2.7 Expected dividend yield — —
Summary of change in fair value of derivative warrant liabilities	The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the three months ended March 31, 2024 (in thousands): Private Placement Warrant Liability Balance at December 31, 2023 $ 40 Change in fair value — Balance at March 31, 2024 $ 40

Property and Equipment , net (T

Property and Equipment , net (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment ,net	Property and equipment, net consists of the following (in thousands): March 31, December 31, Lab equipment $ 108 $ 30 Computer and office equipment 154 154 Furniture and fixtures 78 78 Leasehold improvements 188 188 Construction in process 14 14 542 464 Less accumulated depreciation and amortization ( 352 ) ( 324 ) $ 190 $ 140

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): March 31, December 31, Employee compensation $ 978 $ 1,587 Research and development 2,461 1,036 Professional and outside services 131 75 Interest 217 223 $ 3,787 $ 2,921

Term Loans (Tables)

Term Loans (Tables)	3 Months Ended
	Mar. 31, 2024
Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]
Schedule of Principal Future Payments of Term Loans	Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of March 31, 2024 (in thousands): As of March 31, 2024 Remainder of 2024 $ 5,000 2025 6,667 2026 6,667 2027 1,110 Required future principal payments $ 19,444 Unamortized debt discount ( 528 ) Current term loans, net as of March 31, 2024 $ 18,916

Warrants (Tables)

Warrants (Tables)	3 Months Ended
	Mar. 31, 2024
Class of Warrant or Right [Table]
Summary of Public and private placement warrants outstanding.	The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023: March 31, December 31, Exercise Price Expiration Date Public warrants 233,332 233,332 $ 287.50 August 24, 2026 Private placement warrants 7,266 7,266 $ 287.50 August 24, 2026
Warrant [Member]
Class of Warrant or Right [Table]
Summary of Public and private placement warrants outstanding.	The common stock warrants, placement agent warrants and pre-funded warrants are equity-classified. The following table summarizes the number of outstanding common stock warrants, placement agent warrants and pre-funded warrants and the corresponding exercise price as of March 31, 2024 and December 31, 2023: March 31, December 31, Exercise Price Expiration Date May 2023 Common Stock Warrants 458,015 458,015 $ 13.25 November 30, 2028 May 2023 Placement Agent Warrants 32,060 32,060 $ 20.47 May 26, 2028 June 2023 Common Stock Warrants 310,577 310,577 $ 25.00 December 8, 2028 June 2023 Placement Agent Warrants 21,739 21,739 $ 35.1575 June 6, 2028 January 2024 Pre-funded Warrants 653,000 — $ 0.001 N/A January 2024 Common Stock Warrants 1,488,834 — $ 9.95 July 29, 2027 January 2024 Placement Agent Warrants 104,218 — $ 12.5938 July 29, 2027

Preferred Stock and Stockhold_2

Preferred Stock and Stockholders' Deficit (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Summary of option activity under the company's plans	A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years): Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2023 480,875 $ 51.67 7.3 $ — Granted 231,800 11.32 9.9 Cancelled or forfeited ( 17,911 ) 13.53 3.9 Outstanding at March 31, 2024 694,764 $ 39.19 7.9 $ 1,039 Vested and exercisable at March 31, 2024 325,122 $ 56.29 6.3 $ 151
Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants.	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows: Three Months Ended March 31, 2024 2023 Risk-free interest rate 4.3 % 3.6 % - 4.1 % Expected volatility 84 % - 85 % 84 % Expected term (in years) 5.3 - 6.0 5.3 - 6.1 Expected dividend yield 0 % 0 %
Schedule of Common Stock, Reserved for Future Issuance	Common stock reserved for future issuance consists of the following as of March 31, 2024 and December 31, 2023: March 31, December 31, Stock options issued and outstanding 694,764 480,875 Public warrants issued and outstanding 233,332 233,332 Private placement warrants issued and outstanding 7,266 7,266 Common stock warrants issued and outstanding 2,257,426 768,592 Placement agent warrants issued and outstanding 158,017 53,799 Pre-funded warrants 653,000 — Unvested sponsor shares 12,000 12,000 Authorized for future stock awards or option grants 32,293 96,449 Authorized for future issuances under the ESPP 89,090 59,144 Total 4,137,188 1,711,457

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Supplemental Balance sheet Information related to Leases	The following table summarizes supplemental balance sheet information related to leases as of March 31, 2024 and December 31, 2023 (in thousands): March 31, December 31, Assets: Operating lease right-of-use assets $ 225 $ 53 Total right-of-use assets 225 53 Liabilities Operating lease liabilities, current 53 60 Operating lease liabilities, non-current 179 — Total operating lease liabilities $ 232 $ 60
Schedule of Future Minimum Rental Payments for Operating Leases	As of March 31, 2024, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate): Remainder of 2024 $ 56 2025 77 2026 79 2027 68 Total remaining lease payments 280 Less: imputed interest ( 48 ) Total operating lease liabilities 232 Less: current portion ( 53 ) Long-term operating lease liabilities $ 179 Weighted-average remaining lease term ( in years ) 3.60 Weighted-average discount rate 11.5 %

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares	Jan. 09, 2024 $ / shares	Dec. 31, 2023 USD ($) $ / shares
Subsidiary Sale Of Stock [Line Items]
Place of incorporation	DE
Accumulated deficit	$ 188,211		$ 179,377
Cash from operation	7,300
Cash & Cash Equivalents in Securities	$ 25,400
Date of incorporation	Oct. 02, 2020
Common stock price per share | $ / shares	$ 0.0001		$ 0.0001
Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Common stock price per share | $ / shares	$ 0.0001	$ 0.0001
Maximum [Member] | Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Shares issued | shares	1,000,000,000
Minimum [Member] | Common Stock [Member]
Subsidiary Sale Of Stock [Line Items]
Shares issued | shares	40,000,000
Locust Walk Acquisition Corp [Member]
Subsidiary Sale Of Stock [Line Items]
Conversion of outstanding common and preferred shares into common shares	0.09657

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	Mar. 31, 2024 $ / shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Exercise price of warrants	$ 0.001

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of basic and diluted net income (loss) per share (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic Net Income (Loss) per share
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Net loss per share - Basic	$ (2.16)	$ (5.96)
Diluted Net income (Loss) per share
Weighted average common shares outstanding - basic	4,081,580	1,680,032
Weighted average common shares outstanding - diluted	4,081,580	1,680,032
Net loss per share - diluted	$ (2.16)	$ (5.96)

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities (Detail) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	3,362,805	926,498
Common Stock Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	2,257,426	0
Placement agent warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	158,017	0
Public warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	233,332	233,332
Private Placement [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	7,266	7,266
Earn-Out Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	0	200,000
Unvested sponsor shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	12,000	12,000
Stock Options Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	694,764	473,900

Fair Value Measurementsn - Addi

Fair Value Measurementsn - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash & Cash Equivalents in Securities	$ 25,400
Short-term investments	9,875	$ 3,495
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, net derivative asset (liability) measured on recurring basis, unobservable inputs reconciliation, transfers, net	0	0
Investments in money market fund	6,000	10,900
Marketable Securities	19,300	7,500
Interest Receivable	17,000	52,000
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash & Cash Equivalents in Securities	9,500	4,000
Short-term investments	$ 9,900	$ 3,500

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets And Liabilities Measured At Fair Value On Recurring Basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Total assets	$ 25,383	$ 18,370
Liabilities
Total liabilities	40	40
US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,460	3,988
Private Placement Warrant Liability
Liabilities
Warrant liability	40	40
Fair Value Inputs Level 1
Assets
Total assets	6,048	10,887
Liabilities
Total liabilities	0	0
Fair Value Inputs Level 2
Assets
Total assets	19,335	7,483
Liabilities
Total liabilities	0	0
Fair Value Inputs Level 2 | US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,460	3,988
Fair Value Inputs Level 3
Assets
Total assets	0	0
Liabilities
Total liabilities	40	40
Fair Value Inputs Level 3 | Private Placement Warrant Liability
Liabilities
Warrant liability	40	40
Money Market Funds
Assets
Money market funds	6,048	10,887
Money Market Funds | Fair Value Inputs Level 1
Assets
Money market funds	6,048	10,887
Short-Term Investments [Member] | US Treasury Securities [Member]
Assets
U.S. Treasury securities	9,875	3,495
Short-Term Investments [Member] | Fair Value Inputs Level 2 | US Treasury Securities [Member]
Assets
U.S. Treasury securities	$ 9,875	$ 3,495

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Short term Investment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 9,875	$ 3,495
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	$ 9,875	$ 3,495
U.S. Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year	1 year
Amortized Cost	$ 9,875	$ 3,495
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	$ 9,875	$ 3,495

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of change in fair value of preferred stock warrant liability (Detail) - Series C Preferred Stock Warrant Liability [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, Beginning Balance	$ 40
Change in fair value	0
Fair value, Ending Balance	$ 40

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of fair value measurements inputs of private placement warrant liability (Detail) - Private Placement Warrant Liability	Mar. 31, 2024 USD ($) yr	Dec. 31, 2023 yr USD ($)
Common Stock Price
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | $	14.39	11.69
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	125	125
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	4.5	4.1
Expected term (in years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | yr	2.4	2.7
Expected dividend yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	0	0

Property and Equipment, net - S

Property and Equipment, net - Summary of Property and Equipment, net (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 542	$ 464
Less accumulated depreciation and amortization	(352)	(324)
Property and Equipment, Net	190	140
Lab Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	108	30
Computer And Office Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	154	154
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	78	78
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	188	188
Construction In Progress
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 14	$ 14

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 28,000	$ 28,000

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Employee compensation	$ 978	$ 1,587
Research and development	2,461	1,036
Professional and outside services	131	75
Interest	217	223
Accrued Liabilities, Current	$ 3,787	$ 2,921

Term Loans - Additional Informa

Term Loans - Additional Information (Detail) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 22, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)	Mar. 31, 2021 USD ($) Tranche	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares		$ 0.001
Outstanding principal, Term loans		$ 18,916
Extended cut off date before which the interest on term loan shall be paid	Mar. 01, 2024
Long term debt net of unamortized debt discounts		$ 19,444
Loan and Security Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Number of tranches | Tranche				2
Debt instrument, face amount				$ 30,000
Number of days within which a portion of term loan will be available subject to achievement of milestone	45 days
Long term debt variable interest rate percentage		7.70%
Loan and Security Agreement [Member] | Prime Rate [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument variable interest rate spread		4.45%
Loan and Security Agreement [Member] | Warrants To Purchase Series C Redeemable Convertible Stock | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares		$ 133.25
Number of shares subject to each warrant | shares		1,503
Loan and Security Agreement [Member] | Debt Instrument, Term Loan A [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt Instrument, Discount		$ 1,600
Outstanding principal, Term loans		19,400		$ 20,000	$ 20,000
Amortization of debt discount		700	$ 700
Extended maturity of Term A Loans, Description	In connection with the amendment, the maturity of the Term A Loans was extended from March 18, 2026 to February 1, 2027.
Term loan final payment as a percentage of the amount funded				5.50%
Long term debt net of unamortized debt discounts		$ 18,900		$ 20,000	$ 19,400
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member]
Debt Instrument [Line Items]
Term Loans Additional	$ 10,000
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member] | Less Than One Year From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Loan initiation date	Jun. 30, 2023
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 10,000

Term Loans - Schedule of Princi

Term Loans - Schedule of Principal Future Payments of Term Loans (Detail) $ in Thousands	Mar. 31, 2024 USD ($)
Notes and Loans Payable, by Type, Current and Noncurrent [Abstract]
Remainder of 2024	$ 5,000
2025	6,667
2026	6,667
2027	1,110
Required future principal payments	19,444
Unamortized debt discount	(528)
Current term loans, net as of March 31, 2024	$ 18,916

Warrants - Additional Informati

Warrants - Additional Information (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Public Warrants and Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants	287.5
Class of warrants, redemption price per unit	$ 0.25
Class of warrants, redemption notice period	30 days
Share price	$ 450
Warrants and rights outstanding, term	5 years
Number of consecutive trading days for determining share price	20 days
Number of trading days to determine share price	30 days
May 2023 Registered Direct Offering
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.025
Class of Warrant or Right, Outstanding	270,015
Pre-funded warrants with a purchase price	$ 16.35
May 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 20.47
Class of Warrant or Right, Outstanding	32,060	32,060
Expiration date	May 26, 2028
May 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 13.25
Class of Warrant or Right, Outstanding	458,015	458,015
Expiration date	Nov. 30, 2028
June 2023 Registered Direct Offering
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.025
Class of Warrant or Right, Outstanding	72,578
Pre-funded warrants with a purchase price	$ 28.1
June 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 25
Class of Warrant or Right, Outstanding	310,577	310,577
Expiration date	Dec. 08, 2028
June 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 35.1575
Class of Warrant or Right, Outstanding	21,739	21,739
Expiration date	Jun. 06, 2028
January 2024 Registered Direct Offering
Class of Warrant or Right [Line Items]
Warrants exercise	497,834
Exercise price of warrants	$ 0.001
Class of Warrant or Right, Outstanding	1,150,834
Pre-funded warrants with a purchase price	$ 10.074
January Two Thousand Twenty Four Pre-funded Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Class of Warrant or Right, Outstanding	653,000	0
January 2024 Common Stock Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 9.95
Class of Warrant or Right, Outstanding	1,488,834	0
Expiration date	Jul. 29, 2027
January 2024 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 12.5938
Class of Warrant or Right, Outstanding	104,218	0
Expiration date	Jul. 29, 2027

Warrants - Schedule of Public a

Warrants - Schedule of Public and private placement warrants outstanding (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class of Warrant or Right [Line Items]
Exercise price of warrants	$ 0.001
Public Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	233,332	233,332
Exercise price of warrants	$ 287.5
Expiration date	Aug. 24, 2026
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	7,266	7,266
Exercise price of warrants	$ 287.5
Expiration date	Aug. 24, 2026
May 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	458,015	458,015
Exercise price of warrants	$ 13.25
Expiration date	Nov. 30, 2028
May 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	32,060	32,060
Exercise price of warrants	$ 20.47
Expiration date	May 26, 2028
June 2023 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	310,577	310,577
Exercise price of warrants	$ 25
Expiration date	Dec. 08, 2028
June 2023 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	21,739	21,739
Exercise price of warrants	$ 35.1575
Expiration date	Jun. 06, 2028
January 2024 Pre-funded Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	653,000	0
Exercise price of warrants	$ 0.001
January 2024 Common Stock Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	1,488,834	0
Exercise price of warrants	$ 9.95
Expiration date	Jul. 29, 2027
January 2024 Placement Agent Warrants
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	104,218	0
Exercise price of warrants	$ 12.5938
Expiration date	Jul. 29, 2027

Equity Purchase Agreement (Addi

Equity Purchase Agreement (Additional Information) (Details) $ in Millions	Jan. 24, 2022 USD ($)
Purchase Agreement [Member]
Defined Benefit Plan Disclosure [Line Items]
Other expense relating to the commitment fee	$ 0.8

Preferred Stock and Stockhold_3

Preferred Stock and Stockholders' Equity - Additional Information (Detail)			3 Months Ended
	Sep. 30, 2022 USD ($)	Jan. 24, 2022 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) TradingDays $ / shares shares	Mar. 31, 2023 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares shares	Aug. 24, 2021 shares
Class Of Stock [Line Items]
Preferred Stock, Shares authorized | shares			100,000,000		100,000,000
Preferred stock, par value | $ / shares			$ 0.0001		$ 0.0001
Common Stock Value			$ 0		$ 0
Proceeds from exercise of common stock options and prefunded warrants			$ 1,000	$ 0
Preferred stock, shares outstanding | shares			0		0
Stock options outstanding | shares			694,764		480,875
Common stock, shares issued | shares			3,914,309		2,994,679
Number of Option Outstanding,Granted | shares			231,800
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares			$ 100
Increase in reserved shares, percentage | $ / shares			$ 110
No share purchases under the Purchase Agreement | shares			0	0
Fair value of vested option			$ 1,000,000
Share-based Payment Arrangement, Expense			1,000,000	$ 1,200,000
Unrecognized compensation cost related to outstanding employee options			$ 5,600,000
Expected term (in years)			2 years 9 months 18 days
Maximum [Member]
Class Of Stock [Line Items]
Expected term (in years)			6 years	6 years 1 month 6 days
Minimum [Member]
Class Of Stock [Line Items]
Expected term (in years)			5 years 3 months 18 days	5 years 3 months 18 days
Holder of More Than 10% [Member]
Class Of Stock [Line Items]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares			$ 10
Purchase Agreement [Member]
Class Of Stock [Line Items]
Other expense relating to the commitment fee		$ 800,000
Lincoln Park [Member]
Class Of Stock [Line Items]
Purchase Agreement		36 months
Initial Purchase Amount		$ 3,000,000
Initial purchase number of shares | shares		22,304
Shares issued, commitment shares | shares		5,717
Lincoln Park [Member] | Maximum [Member]
Class Of Stock [Line Items]
Available for sales of common shares under the facility		$ 50,000,000
Lincoln Park [Member] | Regular Purchase [Member]
Class Of Stock [Line Items]
Trading volume percentage		25%
Percentage of common shares outstanding prior to the execution of purchase agreement		97%
Sponsor Shares [Member]
Class Of Stock [Line Items]
Stock options outstanding | shares			162,250
Share based compensation options vesting shares | shares			12,000
Sponsor Shares [Member] | Maximum [Member]
Class Of Stock [Line Items]
Trading days | TradingDays			30
Sponsor Shares [Member] | Minimum [Member]
Class Of Stock [Line Items]
Trading days | TradingDays			20
Atm Offering Program Member
Class Of Stock [Line Items]
Payments Of Commission Percentage	3%
Preferred Units, Offering Costs	$ 6,800,000
Proceeds from exercise of common stock options and prefunded warrants			$ 900,000
Shares Issued Price Per Share | $ / shares			$ 11.07
Common stock, shares issued | shares			83,948
Temporary equity underwriting discounts, commissions and fees			$ 100,000
Atm Offering Program Member | Maximum [Member]
Class Of Stock [Line Items]
Common Stock Value	$ 50,000,000
2013, Equity Incentive Plan
Class Of Stock [Line Items]
Stock options outstanding | shares			130,617
June Two Thousand Twenty Three Registered Direct Offering [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 900,000
Net Proceed			7,800,000
Proceeds from exercise of common stock options and prefunded warrants			$ 8,700,000
Shares Issued Price Per Share | $ / shares			$ 28.125
Common stock, shares issued | shares			238,000
January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 1,400,000
Net Proceed			13,600,000
Proceeds from exercise of common stock options and prefunded warrants			$ 15,000,000
Shares Issued Price Per Share | $ / shares			$ 10.075
Common stock, shares issued | shares			338,000
2021, Equity Incentive Plan
Class Of Stock [Line Items]
Shares authorized | shares			596,440
Shares purchased for award | shares			607,306
Number of shares reserved for future issuance | shares			32,293
Shares grants | shares			32,293
2021 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Shares fair market value percentage						85%
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Increase in Reserved Shares						1%
Number of shares reserved for future issuance | shares			89,090			35,200
Shares grants | shares			89,090			35,200
2021 Employee Stock Purchase Plan [Member] | Maximum [Member]
Class Of Stock [Line Items]
Number of shares reserved for future issuance | shares						600,000
Shares grants | shares						600,000
May Two Thousand Twenty Three Register Direct Offering [Member]
Class Of Stock [Line Items]
Amortization Of Sales Commissions			$ 800
Net Proceed			6,700,000
Proceeds from exercise of common stock options and prefunded warrants			$ 7,500,000
Shares Issued Price Per Share | $ / shares			$ 16.375
Common stock, shares issued | shares			188,000
Common Stock [Member] | Lincoln Park [Member]
Class Of Stock [Line Items]
Ownership percentage		4.99%
Common Stock [Member] | Lincoln Park [Member] | Maximum [Member]
Class Of Stock [Line Items]
Purchase shares | shares		1,200
Common Stock [Member] | Lincoln Park [Member] | Purchase Agreement [Member]
Class Of Stock [Line Items]
Price per share | $ / shares		$ 160.5
Percentage of common shares outstanding prior to the execution of purchase agreement		19.99%
Aggregate number of common shares | shares		325,357
Common Stock [Member] | Lincoln Park [Member] | Regular Purchase [Member]
Class Of Stock [Line Items]
Regular Purchase, Description		The Fully Adjusted Regular Purchase Share Limit may be increased as follows: to up to 2,000 shares if the closing price is not below $125.00, and up to 3,000 shares if the closing price is not below $250.00.
Committed obligation amount		$ 500,000,000
Common Stock [Member] | Lincoln Park [Member] | Regular Purchase [Member] | Maximum [Member]
Class Of Stock [Line Items]
Purchase shares | shares			1,200
Common Stock [Member] | Sponsor Shares [Member]
Class Of Stock [Line Items]
Shares Issued Price Per Share | $ / shares			$ 375
Common Stock [Member] | 2021 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares			0	0
Employee Option [Member]
Class Of Stock [Line Items]
Weighted-average grant date fair value | $ / shares			$ 8.27
Non-Employee Option [Member]
Class Of Stock [Line Items]
Weighted-average grant date fair value | $ / shares			$ 8.27
Unrecognized compensation cost related to outstanding employee options			$ 600,000
Expected term (in years)			1 year
H.C. Wainwright & Co [Member] | January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
Costs and Expenses, Total			$ 50,000,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | June Two Thousand Twenty Three Registered Direct Offering [Member]
Class Of Stock [Line Items]
gross proceed			7%
Managemengt fees percentage			1%
Costs and Expenses, Total			$ 50,000,000
clearing fees			$ 15,950,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | January Two Thousand Twenty Four Registered Direct Offering Member [Member]
Class Of Stock [Line Items]
gross proceed			7%
Managemengt fees percentage			1%
Costs and Expenses, Total			$ 25,000,000
clearing fees			$ 15,950,000
H.C. Wainwright & Co [Member] | Private Placement [Member] | May Two Thousand Twenty Three Register Direct Offering [Member]
Class Of Stock [Line Items]
gross proceed			7%
Managemengt fees percentage			1%
Costs and Expenses, Total			$ 75,000,000
clearing fees			$ 15,950,000

Preferred Stock and Stockhold_4

Preferred Stock and Stockholders' Equity - Summary of Option Activity Under the Company's Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Equity [Abstract]
Number of Option Outstanding,Beginning balance	480,875
Number of Option Outstanding,Granted	231,800
Number of Option Outstanding, Cancelled or forfeited	(17,911)
Number of Option Outstanding,Ending balance	694,764	480,875
Number of Option Exercisable	325,122
Weighted Average Exercise Price,Beginning balance	$ 51.67
Weighted Average Exercise Price,Granted	11.32
Weighted average exercise price,Cancelled	13.53
Weighted Average Exercise Price,Ending balance	39.19	$ 51.67
Weighted Average Exercise Price,Exercisable	$ 56.29
Weighted- Average Remaining Contractual Term,Beginning balance	7 years 10 months 24 days	7 years 3 months 18 days
Weighted- Average Remaining Contractual Term,Granted	9 years 10 months 24 days
Weighted- Average Remaining Contractual Term,Cancelled	3 years 10 months 24 days
Weighted- Average Remaining Contractual Term, Ending balance	7 years 10 months 24 days	7 years 3 months 18 days
Weighted- Average Remaining Contractual Term,Exercisable	6 years 3 months 18 days
Aggregate Intrinsic Value,Beginning balance	$ 0
Aggregate Intrinsic Value,Ending balance	1,039	$ 0
Aggregate Intrinsic Value,Exercisable	$ 151

Preferred Stock and Stockhold_5

Preferred Stock and Stockholders' Equity - Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants (Detail)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	4.30%
Expected volatility		84%
Expected term (in years)	2 years 9 months 18 days
Expected dividend yield	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		3.60%
Expected volatility	84%
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		4.10%
Expected volatility	85%
Expected term (in years)	6 years	6 years 1 month 6 days

Preferred Stock and Stockhold_6

Preferred Stock and Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Stock options issued and outstanding	694,764	480,875
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants	$ 2,257,426	$ 768,592
Placement agent warrants issued and outstanding	$ 158,017	$ 53,799
Pre-funded Warrants	653,000	0
Unvested Shares Held By Sponsors	12,000	12,000
Authorized for future stock awards or option grants	32,293	96,449
Authorized for future issuances under the ESPP	89,090	59,144
Total	4,137,188	1,711,457
Public Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	233,332	233,332
Private Placement Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	7,266	7,266
Common Stock [Member]
Class Of Stock [Line Items]
Stock options issued and outstanding	694,764	480,875

Earn-Out Shares - Additional In

Earn-Out Shares - Additional Information (Detail) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Common stock price per share	$ 0.0001	$ 0.0001
Common stock, shares issued	3,914,309	2,994,679

Earn-Out Shares - Summary of Ac

Earn-Out Shares - Summary of Activity for Earn-Out Liability (Detail) - Series C Preferred Stock Warrant Liability [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	$ 40
Change in fair value	0
Fair value, Ending Balance	$ 40

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Aug. 31, 2021	Jul. 31, 2021
License Agreement Disclosure [Line Items]
Research and development	$ 5,306,000	$ 6,609,000
Regents of the University of California [Member]
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement			$ 1,000,000
Research and development	$ 15,000	$ 15,000
Regents of the University of California [Member] | Amendment to the License Agreement [Member]
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement				$ 1,000,000
Regents of the University of California [Member] | Amendment to the License Agreement [Member] | Certain Clinical and Regulatory Milestones [Member]
License Agreement Disclosure [Line Items]
Remaining milestone payments payable				$ 375,000

Research Collaboration and Li_2

Research Collaboration and License Agreement - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2019	Mar. 31, 2024	Mar. 31, 2023
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		$ 27,000
Revenue from contract with customer excluding assessed tax		0	$ 0
Based on License [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		25,600
Based on Research Activities [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		1,400
Early Development and Regulatory Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		80,000
Non Early Stage Development Milestones [Member] | Non Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		165,000
Non Early Stage Development Milestones [Member] | Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		70,000
Specified Sales Based Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment		$ 235,000
Pfizer [Member]
Research Collaboration And License Agreement [Line Items]
Upfront payment received	$ 15,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2021
Lessee, Lease, Description [Line Items]
Operating lease, payments	$ 19,000	$ 14,000
Lease term			3 years
Building [Member]
Lessee, Lease, Description [Line Items]
Operating lease, cost	$ 18,000	$ 16,000

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Operating lease right-of-use assets	$ 225	$ 53
Total right-of-use assets	225	53
Liabilities
Operating lease liabilities, current	53	60
Long-term operating lease liabilities	179	0
Total operating lease liabilities	$ 232	$ 60

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Rental Payments for Operating Leases (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2024	$ 56
2025	77
2026	79
2027	68
Total remaining lease payments	280
Less: imputed interest	(48)
Total operating lease liabilities	232	$ 60
Less: current portion	(53)
Long-term operating lease liabilities	$ 179	$ 0
Weighted-average remaining lease term (in years)	3 years 7 months 6 days
Weighted-average discount rate	11.50%

Employee Benefits (Additional I

Employee Benefits (Additional Information) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Retirement Benefits [Abstract]
Defined Contribution Plan, Cost	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Mar. 31, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
Common Stock, Value, Issued		$ 0	$ 0
Atm Offering Program Member
Subsequent Event [Line Items]
Payments Of Commission Percentage	3%
Maximum | Atm Offering Program Member
Subsequent Event [Line Items]
Common Stock, Value, Issued	$ 50,000