Eledon Pharmaceuticals (ELDN) 10-K 28 Mar 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Mar. 25, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	ELDN
Entity Registrant Name	ELEDON PHARMACEUTICALS, INC.
Entity Central Index Key	0001404281
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity File Number	001-36620
Entity Tax Identification Number	20-1000967
Entity Address, Address Line One	19900 MacArthur Boulevard
Entity Address, Address Line Two	Suite 550
Entity Address, City or Town	Irvine
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92612
City Area Code	(949)
Local Phone Number	238-8090
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		24,813,130
Entity Public Float			$ 25,607,310
Auditor Firm ID	170
Auditor Name	KMJ Corbin & Company LLP
Auditor Location	Irvine, California
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2024 Annual Meeting of Stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end December 31, 2023 , are incorporated by reference into Items 10, 11, 12, 13 and 14 of Part III of this Annual Report on Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 4,612,000	$ 56,409,000
Short-term investments	46,490,000	0
Prepaid expenses and other current assets	5,027,000	3,109,000
Total current assets	56,129,000	59,518,000
Operating lease asset, net	365,000	739,000
In-process research and development	32,386,000	32,386,000
Other assets	186,000	150,000
Total assets	89,066,000	92,793,000
Current liabilities:
Accounts payable	967,000	2,200,000
Current operating lease liability	383,000	363,000
Accrued expenses and other liabilities	2,545,000	3,912,000
Total current liabilities	3,895,000	6,475,000
Deferred tax liability	1,752,000	1,752,000
Non-current operating lease liability	0	383,000
Total liabilities	5,647,000	8,610,000
Commitments and contingencies (Note 8)
Stockholders’ equity:
Common stock, $0.001 par value, 200,000,000 shares authorized at December 31, 2023 and 2022; 24,213,130 and 13,776,788 shares issued and outstanding at December 31, 2023 and 2022, respectively	24,000	14,000
Additional paid-in capital	326,586,000	287,034,000
Accumulated deficit	(243,191,000)	(202,865,000)
Total stockholders’ equity	83,419,000	84,183,000
Total liabilities and stockholders’ equity	89,066,000	92,793,000
Series X1 Non-voting Convertible Preferred Stock [Member]
Stockholders’ equity:
Preferred stock, value
Series X Non-voting Convertible Preferred Stock [Member]
Stockholders’ equity:
Preferred stock, value

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	24,213,130	13,776,788
Common stock, shares outstanding	24,213,130	13,776,788
Series X1 Non-voting Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	515,000	515,000
Preferred stock, shares issued	110,086	117,970
Preferred stock, shares outstanding	110,086	117,970
Series X Non-voting Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	4,422	6,204
Preferred stock, shares outstanding	4,422	6,204

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses
Research and development	$ 30,312,000	$ 27,080,000
General and administrative	12,688,000	12,700,000
Goodwill impairment	0	48,648,000
Total operating expenses	43,000,000	88,428,000
Loss from operations	(43,000,000)	(88,428,000)
Other income, net	2,674,000	462,000
Loss before income taxes	(40,326,000)	(87,966,000)
Income taxes	0	0
Net loss and comprehensive loss	$ (40,326,000)	$ (87,966,000)
Net loss per share, basic	$ (1.64)	$ (6.16)
Net loss per share, diluted	$ (1.64)	$ (6.16)
Weighted-average common shares outstanding, basic	24,619,197	14,285,254
Weighted-average common shares outstanding, diluted	24,619,197	14,285,254

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Series X1 Non-voting Convertible Preferred Stock [Member]	Series X Non Voting Convertible Preferred Stock [Member]
Beginning Balance at Dec. 31, 2021	$ 163,995	$ 14	$ 278,880	$ (114,899)
Beginning Balance, Shares at Dec. 31, 2021		14,306,788			108,070	6,204
Cancellation of common stock in connection with exchange for preferred stock	1		1
Cancellation of common stock in connection with exchange for preferred stock, Shares		(550,000)			9,900
Issuance of common stock in connection with vesting of restricted stock units		20,000
Stock-based compensation	8,153		8,153
Net loss and other comprehensive loss	(87,966)			(87,966)
Ending Balance at Dec. 31, 2022	84,183	$ 14	287,034	(202,865)
Ending Balance, Shares at Dec. 31, 2022		13,776,788			117,970	6,204
Issuance of common stock and pre-funded warrants in connection with Securities Purchase Agreement, net of issuance costs, Shares		8,730,168
Issuance of common stock and pre-funded warrants in connection with Securities Purchase Agreement, net of issuance costs, Value	33,017	$ 9	33,008
Issuance of common stock in connection with conversion of X non-voting convertible preferred stock, Shares		99,000				(1,782)
Issuance of common stock in connection with conversion of X1 non-voting convertible preferred stock, Shares		437,977			(7,884)
Issuance of common stock in connection with conversion of X1 non-voting convertible preferred stock, Value	(1)		(1)
Issuance of common stock in connection with exercise of pre-funded warrants, Shares		1,154,197
Issuance of common stock in connection with exercise of pre-funded warrants, Value	1	$ 1
Issuance of common stock in connection with vesting of restricted stock units		15,000
Stock-based compensation	6,545		6,545
Net loss and other comprehensive loss	(40,326)			(40,326)
Ending Balance at Dec. 31, 2023	$ 83,419	$ 24	$ 326,586	$ (243,191)
Ending Balance, Shares at Dec. 31, 2023		24,213,130			110,086	4,422

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows used in operating activities:
Net loss	$ (40,326,000)	$ (87,966,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of operating lease asset	374,000	373,000
Accretion on investment discounts	(1,203,000)
Goodwill impairment	0	48,648,000
Stock-based compensation	6,545,000	8,153,000
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,954,000)	654,000
Accounts payable, accrued expenses and other liabilities	(2,600,000)	2,081,000
Operating lease liabilities	(363,000)	(367,000)
Net cash used in operating activities	(39,527,000)	(28,424,000)
Cash flows from investing activities:
Purchase of available-for-sale short-term investments	(78,287,000)
Proceeds from maturities of available-for-sale short-term investments	33,000,000
Net cash used in investing activities	(45,287,000)
Cash flows from financing activities:
Proceeds from issuances of common stock and pre-funded warrants, net	33,017,000
Net cash used in financing activities	33,017,000
Net change in cash and cash equivalents	(51,797,000)	(28,424,000)
Cash and cash equivalents at beginning of year	56,409,000	84,833,000
Cash and cash equivalents at end of year	4,612,000	56,409,000
Non-cash activities:
Common stock exchanged for X and X1 non-voting convertible preferred stock	$ 1,000	1,000
Increase in operating lease asset and liability due to lease modification		$ 344,000

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Description of Business	Note 1. Description of Business Eledon Pharmaceuticals, Inc. is a clinical stage biotechnology company using its immunology expertise in targeting the CD40 Ligand (“CD40L” or “CD154”) pathway to develop therapies to protect transplanted organs and prevent rejection, and to treat amyotrophic lateral sclerosis (“ALS”). The Company’s lead compound in development is tegoprubart, an IgG1, anti-CD40L antibody with high affinity for the CD40 Ligand, a well-validated biological target that we believe has broad therapeutic potential. Unless otherwise indicated, references to the terms “Eledon,” “our,” “us,” “we,” or the “Company” refer to Eledon Pharmaceuticals, Inc. and its wholly owned subsidiaries, on a consolidated basis. On September 14, 2020 , Eledon acquired Anelixis Therapeutics, Inc. (“Anelixis”), a privately held clinical stage biotechnology company developing a next generation anti-CD40L antibody as a potential treatment for organ and cellular transplantation, autoimmune diseases, and neurodegenerative diseases. The Company maintains its corporate headquarters in Irvine, California and has research and development facilities in Burlington, Massachusetts.

Going Concern and Management's

Going Concern and Management's Plans	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Going Concern and Management's Plans	Note 2. Going Concern and Management’s Plans The accompanying consolidated financial statements have been prepared under the assumption the Company will continue to operate as a going concern, which contemplates the realization of assets and the settlement of liabilities in the normal course of business. The consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts of liabilities that may result from uncertainty related to the Company’s ability to continue as a going concern. The Company had a net loss of $ 40.3 million for the year ended December 31, 2023 and an accumulated deficit of $ 243.2 million as of December 31, 2023, as a result of incurring losses since our inception. Due to continuing research and development activities, the Company expects to continue to incur net losses into the foreseeable future. The Company expects to continue to incur net losses into the foreseeable future in connection with its ongoing activities, particularly as the Company expands its clinical program with tegoprubart, continues the research and development of, and seeks marketing approval for, its product candidates. In addition, if the Company obtains marketing approval for any of its product candidates, the Company expects to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. The Company has financed operations primarily by net proceeds from the sale of preferred and common stock and warrants. On April 28, 2023, the Company entered into a Securities Purchase Agreement (the "Securities Purchase Agreement") with certain institutional and accredited investors (the “Purchasers”), pursuant to which the Company agreed to issue and sell to the Purchasers in a private placement (the “Private Placement”) shares of common stock and warrants in a series of three potential closings. On May 5, 2023, the initial closing occurred and the Company received $ 35.0 million, in exchange for 8,730,168 shares of common stock, pre-funded warrants to purchase 6,421,350 shares of common stock and additional common stock warrants to purchase 15,151,518 shares of common stock (or pre-funded warrants in lieu thereof). The Company may receive up to an additional $ 105.0 million in tranche financing in a second and a third closing, subject to achieving specified clinical development milestones and volume weighted average share price levels and trading volume conditions, and an additional $ 45.5 million assuming the exercise of all common stock warrants issued in the initial closing of the Private Placement. See Note 10. “Stockholders’ Equity” for further information regarding the Private Placement. Due to the contingent nature of the exercise of the common stock warrants and the second and third closings of the Private Placement, accounting principles generally accepted in the United States of America (“GAAP”) requires the Company to exclude them from its going concern analysis. If these events do not occur or the Company is unable to secure additional capital or is unable to do so on acceptable terms, it will be forced to significantly alter its business strategy, substantially curtail its current operations, or liquidate and cease operations altogether. As of December 31, 2023, the Company had cash and cash equivalents and short-term investments of approximately $ 51.1 million. Additionally, in view of the Company’s expectation to incur significant losses for the foreseeable future, the Company will be required to raise additional capital resources in order to fund its operations, although the availability of, and the Company’s access to, such resources is not assured. Accordingly, management believes that there is substantial doubt regarding the Company’s ability to continue operating as a going concern through at least the next twelve months from the date of this filing.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 3. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The consolidated financial statements are prepared in accordance with GAAP. Eledon, a Delaware corporation, owns 100 % of the issued and outstanding common stock or other ownership interest in Anelixis Therapeutics, LLC, a Delaware limited liability company, and Otic Pharma, Ltd., a private limited company organized under the laws of the State of Israel (“Otic”). Otic owns 100 % of the issued and outstanding common stock or other ownership interest in its U.S. subsidiary, Otic Pharma, Inc. The functional currency of the Company’s foreign subsidiary is the U.S. Dollar; however, certain expenses, assets and liabilities are transacted at the local currency. These transactions are translated from the local currency into U.S. Dollars at exchange rates during or at the end of the reporting period. The activities of the Company’s foreign subsidiary are not significant to the consolidated financial statements. All significant intercompany accounts and transactions among the entities have been eliminated in consolidation. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make informed estimates and assumptions that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to stock-based compensation, accruals for liabilities, impairment of long-lived assets, and other matters that affect the consolidated financial statements and related disclosures. Actual results could differ materially from those estimates under different assumptions or conditions and the differences may be material to the consolidated financial statements. Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consists of cash, cash equivalents and short-term investments. The Company maintains deposits in federally insured institutions in excess of federally insured limits and invests in short-term investments with the primary objective of seeking to preserve principal, achieve liquidity requirements and safeguard invested funds. We believe that the Company is not exposed to significant credit risk due to the financial position of the depository institution in which those deposits are held and the nature, including the credit ratings, of our cash equivalents and short-term investments, but we have not eliminated all credit risk. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking accounts, money market funds, U.S. government securities and U.S. government agency securities. Cash and cash equivalents are valued at cost, which approximates their fair value due to the short-term maturities of these investments. Risks and Uncertainties As of December 31, 2023 and 2022, all of the Company’s long-lived assets were located in the United States. The Company’s products will require approval from the U.S. Food and Drug Administration (“FDA”) and foreign regulatory agencies before commercial sales can commence. There can be no assurance that its products will receive any of these required approvals. The denial or delay of such approvals may impact the Company’s business in the future. In addition, after the approval by the FDA, there is still an ongoing risk of adverse events that did not appear during the product approval process. The Company is subject to risks common to companies in the pharmaceutical industry, including, but not limited to, new technological innovations, clinical development risk, establishment of appropriate commercial partnerships, protection of proprietary technology, compliance with government and environmental regulations, uncertainty of market acceptance of products, product liability, the volatility of its stock price and the need to obtain additional financing. The Company's facilities and equipment, including those of the Company's suppliers and vendors, may be affected by natural or man-made disasters. The Company's administrative office is based in Irvine, California and the Company manages all its research and development activities through third parties that are located throughout the world. The Company has taken precautions to safeguard its facilities, equipment and systems, including insurance, health and safety protocols, and off-site storage of computer data. However, the Company's facilities and systems, as well as those of its third-party suppliers and vendors, may be vulnerable to earthquakes, fire, storm, public health or similar emergencies, power loss, telecommunications failures, physical and software break-ins, software viruses and similar events which could cause substantial delays in its operations, damage or destroy its equipment or inventory, and cause the Company to incur additional expenses and delay research and development activities. In addition, the insurance coverage the Company maintains may not be adequate to cover its losses in any circumstance and may not continue to be available to use on acceptable terms, or at all. Reportable Segments Operating segments under GAAP are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the Chief Operating Decision Maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance. The CODM is the Company’s Chief Executive Officer and the Company has determined that it operates in one business segment, which is the development of products for therapeutic medicines selectively targeting critical pathways associated with the underlying molecular pathogenesis for patients with severe inflammation and autoimmune diseases. Goodwill Goodwill represents the difference between the consideration transferred and the fair value of the net assets acquired under the acquisition method of accounting. Goodwill is not amortized but is evaluated for impairment as of December 31 of each year or if indicators of impairment exist that would, more likely than not, reduce the fair value from its carrying amount. The Company performs its goodwill impairment analysis at the reporting unit level, which aligns with the Company’s reporting structure and availability of discrete financial information. The Company performs its annual impairment analysis by either comparing the reporting unit’s estimated fair value to its carrying amount or doing a qualitative assessment of a reporting unit’s fair value from the last quantitative assessment to determine if there is potential impairment. The Company may do a qualitative assessment when the results of the previous quantitative test indicated the reporting unit’s estimated fair value was significantly in excess of the carrying value of its net assets and it does not believe there have been significant changes in the reporting unit’s operations that would significantly decrease its estimated fair value or significantly increase its net assets. If a quantitative assessment is performed, the evaluation includes management estimates of cash flow projections based on internal future projections and/or use of a market approach by looking at market values of comparable companies. Key assumptions for these projections include revenue growth, future gross and operating margin growth, and its weighted cost of capital and terminal growth rates. The revenue and margin growth is based on increased sales of new products as the Company maintains investments in research and development. Additional assumed value creators may include increased efficiencies from capital spending. The resulting cash flows are discounted using a weighted average cost of capital. Operating mechanisms and requirements to ensure that growth and efficiency assumptions will ultimately be realized are also considered in the evaluation, including timing and probability of regulatory approvals for Company products to be commercialized. The Company’s market capitalization is also considered as a part of its analysis. The Company’s annual evaluation for impairment of goodwill consists of one reporting unit. In accordance with the Company’s policy, the Company completed its annual evaluation for impairment using the quantitative assessment, utilizing the market approach and due to declining market conditions, determined that the fair value of the reporting unit was below its carrying value. As a result, the Company recognized $ 48.6 million of goodwill impairment, reducing the goodwill balance to zero for the year ended December 31, 2022, and accordingly, no goodwill impairment was recorded for the year ended December 31, 2023. Long-Lived Assets Property and equipment are recorded at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Additions, major renewals and improvements are capitalized and repair and maintenance costs are charged to expense as incurred. Leasehold improvements are amortized over the remaining life of the initial lease term or the estimated useful lives of the assets, whichever is shorter. The Company reviews property and equipment for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. An impairment loss would be recognized when estimated future undiscounted cash flows relating to the asset are less than its carrying amount. An impairment loss is measured as the amount by which the carrying amount of an asset exceeds its fair value. Significant management judgment is required in the forecast of future operating results that are used in the preparation of expected cash flows. No impairments of long-lived assets have been identified during the years presented. In-Process Research and Development The fair values of in-process research and development (“IPR&D”) projects acquired in a business combination that are not complete are capitalized and accounted for as indefinite-lived intangible assets until completion or abandonment of the related research and development (“R&D”) efforts. Upon successful completion of the project, the capitalized amount is amortized over its estimated useful life. If a project is abandoned, all remaining capitalized amounts are written off immediately. Major risks and uncertainties are often associated with IPR&D projects because we are required to obtain regulatory approvals before marketing the resulting products. Such approvals require completing clinical trials that demonstrate a product candidate is safe and effective. Consequently, the eventual realized value of the acquired IPR&D project may vary from its fair value at the date of acquisition, and IPR&D impairment charges may occur in future periods. Capitalized IPR&D projects are tested for impairment annually and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. We consider various factors for potential impairment, including the current legal and regulatory environment and the competitive landscape. Adverse clinical trial results, significant delays in obtaining marketing approval, the inability to bring a product to market and the introduction or advancement of competitors’ products could result in partial or full impairment of the related intangible assets. Research and Development Expenses Research and development expenses include personnel and facility-related expenses, outside contracted services including clinical trial costs, manufacturing and process development costs, research costs and other consulting services and non-cash stock-based compensation. Research and development costs are expensed as incurred. Amounts due under contracts with third parties may be either fixed fee or fee for service, and may include upfront payments, monthly payments and payments upon the completion of milestones or receipt of deliverables. Non-refundable advance payments under agreements are capitalized and expensed as the related goods are delivered or services are performed. The Company’s contracts with third parties to perform various clinical trial activities in the on-going development of potential products. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows to its vendors. Payments under the contracts depend on factors such as the achievement of certain events, successful enrollment of patients, and completion of portions of the clinical trial or similar conditions. The Company’s accrual for clinical trials is based on estimates of the services received and efforts expended pursuant to contracts with clinical trial centers and clinical research organizations. These contracts may be terminated by the Company upon written notice and the Company is generally only liable for actual effort expended by the organizations to the date of termination, although in certain instances the Company may be further responsible for termination fees and penalties. The Company estimates its research and development expenses and the related accrual as of each balance sheet date based on the facts and circumstances known to the Company at that time. There have been no material adjustments to the Company’s prior period accrued estimates for clinical trial activities through December 31, 2023 . Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, incentive stock options, restricted stock units and warrants are considered to be potentially dilutive securities and are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive. Therefore, basic and diluted net loss per share was the same for the periods presented due to the Company’s net loss position. Basic weighted average shares outstanding for the years ended December 31, 2023 and 2022 include 5,776,270 and 509,117 , respectively, shares underlying pre-funded warrants to purchase common shares. As the shares underlying these pre-funded warrants can be issued for little consideration (an exercise price per share equal to $ 0.001 per share), these shares are deemed to be issued for purposes of basic earnings per share. Year Ended 2023 2022 (In thousands, except share and per share data) Net loss $ ( 40,326 ) $ ( 87,966 ) Net loss per share, basic and diluted $ ( 1.64 ) $ ( 6.16 ) Weighted-average number of common shares 24,619,197 14,285,254 The computation of diluted earnings per share excludes incentive stock options, restricted stock units, and warrants that are anti-dilutive. The following table provides a summary as of December 31, 2023 and 2022 common share equivalents that were excluded because their inclusion would have been anti-dilutive. Year Ended 2023 2022 Stock options outstanding and other equity awards 14,909,155 5,012,035 Common and preferred warrants outstanding 18,577,332 3,127,121 Total 33,486,487 8,139,156 Stock-Based Compensation The Company recognizes compensation expense for all stock-based awards based on the grant-date estimated fair value. The fair value of stock options is determined using the Black-Scholes option pricing model, using assumptions which are subjective and require significant judgment and estimation by management. The risk-free rate assumption was based on observed yields from governmental zero-coupon bonds with an equivalent term. The expected volatility assumption was based on historical volatilities of a group of comparable industry companies whose share prices are publicly available. The peer group was developed based on companies in the pharmaceutical industry. The expected term of stock options represents the weighted-average period that the stock options are expected to be outstanding. Because the Company does not have historical exercise behavior, the Company determined the expected life assumption using the simplified method for stock options granted to employees, which is an average of the options ordinary vesting period and the contractual term. The expected dividend assumption was based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not expect to pay dividends at any time in the foreseeable future. The Company recognizes forfeitures on an actual basis and as such did not estimate forfeitures to calculate stock-based compensation. Restricted Stock Units (“RSUs”) are measured and recognized based on the quoted market price of our common stock on the date of grant. Income Taxes Significant judgment is required in determining the Company’s provision for income taxes, deferred tax assets and liabilities and the valuation allowance recorded against net deferred tax assets. We assess the likelihood that deferred tax assets will be recovered as deductions from future taxable income. The evaluation of the need for a valuation allowance is performed on a jurisdiction-by-jurisdiction basis and includes a review of all available positive and negative evidence. Factors reviewed include projections of pre-tax book income for the foreseeable future, determination of cumulative pre-tax book income after permanent differences, earnings history, and reliability of forecasting. We have provided a valuation allowance on our deferred tax assets as of December 31, 2023 and 2022 because we believe it is more likely than not that a majority of our deferred tax assets will not be realized as of this date. The Company evaluates the accounting for uncertainty in income tax recognized in its consolidated financial statements and determines whether it is more likely than not that a tax position will be sustained upon examination by the appropriate taxing authorities before any part of the benefit is recorded in its consolidated financial statements. For those tax positions where it is “not more likely than not” that a tax benefit will be sustained, no tax benefit is recognized. Where applicable, associated interest and penalties are also recorded. The Company has not accrued any liabilities for any such uncertain tax positions as of December 31, 2023 and 2022. The Company is subject to U.S. federal and state tax authority examinations for all the years since inception due to net operating loss and tax credit carryforwards. The net operating losses and tax credits are subject to adjustment until the statute closes on the year the attributes are ultimately utilized. The Company’s income tax returns are based on calculations and assumptions that are subject to examination by the Internal Revenue Service and other tax authorities. In addition, the calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax regulations. The Company recognizes liabilities for uncertain tax positions based on a two-step process. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50 % likely of being realized upon settlement. While the Company believes it has appropriate support for the positions taken on its tax returns, the Company regularly assesses the potential outcomes of examinations by tax authorities in determining the adequacy of its provision for income taxes. The Company continually assesses the likelihood and amount of potential revisions and adjusts the income tax provision, income taxes payable and deferred taxes in the period in which the facts that give rise to a revision become known. For additional information, see Note 9. Income Taxes. Recent Accounting Pronouncements Issued But Not Adopted In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This update requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU No. 2023-09 is effective for public entities with annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This update requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280, on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023 and for interim periods beginning after December 15, 2024, with early adoptions permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company’s present or future financial position, results of operations or cash flows.

Short-Term Investments

Short-Term Investments	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Short-Term Investments	Note 4. Short-Term Investments The objectives of the Company’s investment policy are to preserve principal, meet the Company's liquidity requirements and safeguard invested funds. Short-term investments consist of U.S. government securities and U.S. government agency securities. The Company has classified these investments as available-for-sale securities, as the sale of such investments may be required prior to maturity to implement management strategies, and therefore has classified all investments with maturity dates beyond three months at the date of purchase as current assets in the accompanying unaudited condensed consolidated balance sheets. Any premium or discount arising at purchase is amortized and/or accreted to interest income as an adjustment to yield using the straight-line method over the life of the instrument. The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. Investments are reported at their estimated fair value. Unrealized gains and losses are included in accumulated other comprehensive loss as a component of stockholders' equity until realized. The following is a summary of short-term investments, which were classified as available-for-sale securities as of December 31, 2023: December 31, 2023 Amortized Cost Fair Value U.S. government securities $ 33,213 $ 33,213 U.S. government agency securities 13,277 13,277 Total short-term investments $ 46,490 $ 46,490 All of the Company's available-for-sale securities have a stated maturity of less than one year. The Company did no t hold any short-term investments as of December 31, 2022 .

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Text Block [Abstract]
Fair Value Measurements	Note 5. Fair Value Measurements Financial assets and liabilities are recorded at fair value. The Company classifies fair value measurements using a three-level hierarchy that prioritizes the inputs used to measure fair value. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1—Quoted market prices (unadjusted) in active markets for identical assets and liabilities. • Level 2—Observable inputs other than quoted market prices included in Level 1, such as quoted market prices for markets that are not active or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, including certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. These fair values are obtained from independent pricing services which utilize Level 1 and Level 2 inputs. The following table summarizes the Company's financial instruments measured at fair value on a recurring basis as of December 31, 2023 and 2022. Included within cash and cash equivalents on the consolidated balance sheets, but excluded from the fair value hierarchy table, are cash deposits held at financial institutions. December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 4,246 $ — $ — $ 4,246 Total cash equivalents 4,246 — — 4,246 Short-term investments: U.S. government securities — 33,213 — 33,213 U.S. government agency securities — 13,277 — 13,277 Total short-term investments — 46,490 — 46,490 Total financial assets $ 4,246 $ 46,490 $ — $ 50,736 December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 9,296 $ — $ — $ 9,296 Total cash equivalents 9,296 — — 9,296 Total financial assets $ 9,296 $ — $ — $ 9,296

Prepaid Expenses, Other Assets,

Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2023
Prepaid Expenses Other Assets Accrued Expenses And Other Liabilities [Abstract]
Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities	Note 6. Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities Prepaid expenses and other current assets consisted of the following as of December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Prepaid insurance $ 624 $ 823 Prepaid clinical 4,128 2,115 Prepaid other 185 143 Other current assets 90 28 Total prepaid expenses and other current assets $ 5,027 $ 3,109 Accrued expenses and other liabilities consisted of the following as of December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Accrued compensation and related expenses $ 2,003 $ 1,909 Accrued clinical 451 1,826 Accrued professional services 47 65 Accrued other 44 112 Total accrued expenses and other liabilities $ 2,545 $ 3,912

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Note 7. Goodwill In 2022, the Company determined that the sustained decrease in our market capitalization constituted an indicator of impairment and as a result, a quantitative goodwill impairment test, utilizing the market approach, determined that the fair value of the reporting unit was below its carrying value and the goodwill was fully impaired. The Company recorded an impairment of $ 48.6 million for the year ended December 31, 2022 for the full write-down of the goodwill recorded as part of the acquisition of Anelixis. No impairment was recorded for the year ended December 31, 2023. Total Balance as of December 31, 2021 $ 48,648 Impairments ( 48,648 ) Balance as of December 31, 2022 $ — Impairments — Balance as of December 31, 2023 $ —

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 8. Commitments and Contingencies Operating Leases The Company leases office space under various operating leases. Total rent expense for all operating leases in the consolidated statements of operations and comprehensive loss was approximately $ 0.4 million for each of the years ended December 31, 2023 and 2022. The Company has an operating lease for 5,197 square feet of office space in Irvine, California, that expires on December 31, 2024 , as amended. On November 4, 2021, the Company entered into an operating lease for 6,138 square feet of office space in Burlington, Massachusetts, that expires on November 20, 2024 . The Company determines if a contract contains a lease at inception. Our office leases have remaining terms of approximately 12 months and do not include options to extend the leases for additional periods. Operating lease assets and liabilities are recognized at the lease commencement date. Operating lease liabilities represent the present value of lease payments not yet paid. Operating lease assets represent our right to use an underlying asset and are based upon the operating lease liabilities as adjusted for prepayments or accrued lease payments, initial direct costs, lease incentives, and impairment of operating lease assets. To determine the present value of lease payments not yet paid, we estimate incremental secured borrowing rates corresponding to the maturities of the leases. As we have no outstanding debt nor committed credit facilities, secured or otherwise, we estimate this rate based on prevailing financial market conditions, comparable company and credit analysis, and management’s judgment. Our leases contain rent escalations over the lease term. We recognize expense for these leases on a straight-line basis over the lease term. Additionally, tenant incentives used to fund leasehold improvements are recognized when earned and reduce our right-of-use asset related to the lease. These are amortized through the right-of-use asset as reductions of expense over the lease term. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. While we do not currently have any lease agreement with lease and non-lease components, we elected to account for lease and non-lease components as separate components. We have elected the short-term lease recognition exemption for all applicable classes of underlying assets. Short-term disclosures include only those leases with a term greater than one month and 12 months or less, and expense is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less, that do not include an option to purchase the underlying asset that we are reasonably certain to exercise, are not recorded on the consolidated balance sheet. The components of lease expense were as follows (in thousands): Year Ended 2023 2022 Operating lease cost (a) $ 400 $ 403 (a) Includes variable operating lease expenses, which are immaterial. Other information related to leases was as follows (in thousands, except lease term and discount rate): Year Ended 2023 2022 Supplemental Cash Flows Information Cash paid for amounts included in the measurement of lease liability: Operating cash flows from operating lease $ 378 $ 387 Operating lease asset obtained in exchange for lease liability: Operating lease $ — $ 344 Remaining lease term Operating lease 0.95 years 1.95 years Discount rate Operating lease 2.49 % 2.49 % Future payments under noncancelable operating leases having initial or remaining terms of one year or more are as follows for the succeeding fiscal year and thereafter (in thousands): Year Ended 2023 2024 388 Total minimum lease payments 388 Less imputed interest ( 5 ) Present value of lease liabilities 383 Less current portion of operating lease liability ( 383 ) Non-current operating lease liability $ — Grants and Licenses ALS Therapy Development Foundation, Inc. License Agreement In May 2015, Anelixis executed a License Agreement (the “Agreement”), which is an exclusive patent rights agreement with ALS Therapy Development Foundation, Inc. (“ALS TDI”) for certain patents and “know-how” of ALS TDI. This agreement continues until the licensee terminates the agreement with ninety days written notice. The Agreement requires license fees payable to ALS TDI, subject to the achievement of certain milestones and other conditions. The first and second milestones of the Agreement are the dosing of the first subjects in a first toxicity study in non-human primates and the dosing of the first patient in a Phase I Clinical Trial, respectively. Both of these milestones were achieved as of December 31, 2018 and 2017. The fee due for the achievement of these milestones was $ 1.0 million each. During 2018 and 2017, Anelixis issued $ 1.0 million worth of its common stock in lieu of making a cash payment. There were no milestones achieved during 2023 or 2022. The Agreement was amended and restated in February 2020, and a first amendment to the restated license agreement was executed in September 2020. As amended in September 2020, the remaining milestone payments for a first licensed product total $ 6.0 million. In the event that the Company develops a second licensed product, the Company is obligated to pay up to $ 2.5 million in additional milestone payments. In addition to the milestone payments, the Company is required to pay ALS TDI an amended annual license maintenance fee of $ 0.1 million beginning on the earlier of January 1, 2022, the Company’s first sublicense, or change in control, as defined in the Agreement. The Company made a $ 0.1 million annual license maintenance fee in each of 2023 and 2022. Furthermore, the Company shall pay ALS TDI fees based on reaching certain levels of annual net sales of any product produced with the patent rights. A royalty in the low single digits will be due on aggregate net sales. Upon the first calendar year of reaching $ 500.0 million in aggregate net sales, the Company shall pay ALS TDI a one-time milestone payment of $ 15.0 million. Upon the first calendar year of reaching $ 1.0 billion in aggregate net sales, the Company is obligated to pay ALS TDI a one-time milestone payment of $ 30.0 million. Lonza Sales AG Inc. License Agreement In September 2018, Anelixis executed a License Agreement (the “Lonza Agreement”), which is a manufacturing know-how rights agreement with Lonza Sales AG Inc. (“Lonza”) for the use of certain processes and know-how related to the manufacture of tegoprubart. The Lonza Agreement continues until the later of the last Valid Claim (as defined therein) or ten years from the First Commercial Sale of tegoprubart, as defined and subject to the conditions therein. A royalty in the low single digits will be due on aggregate net sales of tegoprubart that is manufactured by Lonza or any other third-party or licensee. eGenesis, Inc. Collaboration Agreement In September 2022, and subsequently amended in January 2023, Eledon executed a non-exclusive collaborative research agreement with eGenesis, Inc. (the “eGenesis Agreement”), under which eGenesis will gain access to tegoprubart for eGenesis’ ongoing preclinical research and development xenotransplant studies of human-compatible organs and cells for the treatment of organ failure. eGenesis will pay Eledon for supplies of tegoprubart based on the number of study days per animal needed for the eGenesis preclinical xenotransplant studies. The eGenesis agreement continues until September 2025, unless terminated earlier by either party. Legal Matters The Company and its subsidiaries are not a party to or the subject of any claim or lawsuit that individually or in the aggregate is anticipated to have a material effect on the Company’s results of operations, financial condition or cash flows. Indemnifications In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves future claims that may be made against the Company but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future because of these indemnification obligations. No amounts associated with such indemnifications have been recorded to date. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. There have been no contingent liabilities requiring accrual at December 31, 2023 and 2022 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Note 9. Income Taxes Loss before income taxes are as follows (in thousands): Year Ended 2023 2022 Losses before income taxes: U.S. $ ( 40,525 ) $ ( 88,159 ) Non-U.S. 199 193 Total $ ( 40,326 ) $ ( 87,966 ) The provision (benefit) for income taxes are as follows (in thousands): Year Ended 2023 2022 Current: Federal $ — $ — State — — Foreign — — — — Deferred: Federal — — State — — Foreign — — — — Provision (benefit) for income taxes $ — $ — The Company is subject to income taxes under U.S. tax laws. The Company is subject to an Israeli corporate tax rate of 23 % in 2020 and thereafter. The Company was subject to a blended U.S. tax rate (federal as well as state corporate tax) of 21 % in 2023 and 2022. Significant judgment is required in determining the Company’s provision for income taxes, deferred tax assets and liabilities and the valuation allowance recorded against net deferred tax assets. Deferred tax assets and liabilities are determined using the enacted tax rates in effect for the years in which those tax assets are expected to be realized. A valuation allowance is established when it is more likely than not the future realization of all or some of the deferred tax assets will not be achieved. The evaluation of the need for a valuation allowance is performed on a jurisdiction-by-jurisdiction basis, and includes a review of all available positive and negative evidence. Factors reviewed include projections of pre-tax book income for the foreseeable future, determination of cumulative pre-tax book income after permanent differences, earnings history, and reliability of forecasting. Based on its review, the Company concluded that it was more likely than not that they would not realize the benefit of a portion of its deferred tax assets in the future. This conclusion was based on historical and projected operating performance, as well as the Company’s expectation that its operations will not generate sufficient taxable income in future periods to realize the tax benefits associated with the deferred tax assets within the statutory carryover periods. Therefore, the Company has a valuation allowance on its deferred tax assets as of December 31, 2023. The Company will continue to assess the need for a valuation allowance on its deferred tax assets by evaluating both positive and negative evidence that may exist. Any adjustment to the net deferred tax asset valuation allowance would be recorded in the statement of operations for the period that the adjustment is determined to be required. A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows (in thousands): Year Ended 2023 2022 Statutory federal income tax rate $ ( 8,468 ) $ ( 18,473 ) State income taxes, net of federal tax benefits ( 1,097 ) ( 2,678 ) Tax credits ( 972 ) ( 1,046 ) Stock-based compensation 728 986 Permanent items 9 3 State rate differential 32 274 NOL true-up 2 ( 337 ) Other 566 114 Goodwill impairment — 11,697 Change in valuation allowance 9,200 9,460 Total provision for income taxes $ — $ — Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2023 and 2022 consisted of the following (in thousands): Year Ended 2023 2022 Net operating loss carryforwards $ 18,089 $ 15,230 Research and development tax credits 3,202 2,294 Accruals and reserves 475 452 Research expenditures 10,567 5,264 Stock-based compensation 3,085 2,874 Depreciation and amortization 1,319 1,595 Lease liability 91 179 Total deferred tax assets 36,828 27,888 Right-of-use asset ( 87 ) ( 178 ) Acquired IPR&D ( 7,682 ) ( 7,787 ) Total deferred tax liabilities ( 7,769 ) ( 7,965 ) Less: valuation allowance ( 30,811 ) ( 21,675 ) Net deferred tax liabilities $ ( 1,752 ) $ ( 1,752 ) The following table reconciles the beginning and ending amounts of unrecognized tax benefits for the years presented (in thousands): Year Ended 2023 2022 Gross unrecognized tax benefits at the beginning of the year $ 2,664 $ 1,469 Additions from tax positions taken in the current year 972 914 Additions from tax positions taken in prior years — 281 Gross unrecognized tax benefits at the end of the year $ 3,636 $ 2,664 The deferred income tax assets have been offset by a valuation allowance, as realization is dependent on future earnings, if any, the timing and amount of which are uncertain. The net valuation allowance increased by $ 9.1 million from December 31, 2022 to December 31, 2023. The net valuation allowance increased by $ 9.4 million from December 31, 2021 to December 31, 2022. The Company’s accounting for deferred taxes involves the evaluation of a number of factors concerning the realizability of its net deferred tax assets. The Company primarily considered such factors as its history of operating losses, the nature of the Company’s deferred tax assets, and the timing, likelihood, and amount, if any, of future taxable income during the periods in which those temporary differences and carryforwards become deductible. At present, the Company does not believe that it is more likely than not that the deferred tax assets will be realized; accordingly, a valuation allowance has been established. As of December 31, 2023 and 2022 , the Company had federal net operating loss carryforwards of approximately $ 68.9 million and $ 56.8 million, respectively, available to reduce future taxable income. As of December 31, 2023 and 2022 , the Company also has state net operating loss carryforwards of $ 30.1 million and $ 25.0 million, respectively. Both the federal and state net operating loss carryforwards incurred before 2018 begin expiring in 2035 , if not utilized. The federal net operating losses incurred since 2018 of $ 68.0 million do not expire. The state net operating losses begin to expire in 2035 . As of December 31, 2023 and 2022 , the Company had Israeli net operating losses of $ 7.9 million, which carryforward indefinitely. As of December 31, 2023 and 2022 , the Company had federal research and development tax credit carryforwards of approximately $ 4.0 million and $ 2.4 million, respectively. If not utilized, the carryforwards will begin expiring in 2036 . As of December 31, 2023 and 2022 , the Company has state research and development credit carryforwards or approximately $ 1.5 million and $ 1.2 million, respectively, which will begin expiring in 2030 if not utilized . Pursuant to Internal Revenue Code (“IRC) Sections 382 and 383, annual use of the Company’s net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50 % occurs within a three-year period. The Company has not completed an IRC Section 382/383 analysis regarding the limitation of net operating loss and research and development credit carryforwards. Due to the existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will not impact the Company’s effective tax rate. The Company’s ability to use its remaining net operating loss and tax credit carryforwards may be further limited if the Company experiences a Section 382 ownership change in connection with future changes in our stock ownership. In the United States, the Company files income tax returns in the U.S. Federal jurisdiction, California and Massachusetts. The Company’s tax years for 2018 and forward are subject to examination by the Federal and California tax authorities due to the carryforward of unutilized net operating losses and research and development credits. The Company’s policy is to recognize interest expense and penalties related to income tax matters as a component of income tax expense. There was no accrued interest and penalties associated with uncertain tax positions as of December 31, 2023 and 2022 . The Company has no t recorded any interest or penalties in 2023 or 2022 .

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	Note 10. Stockholders’ Equity Preferred Stock The Company has 5,000,000 authorized shares of preferred stock with a par value of $ 0.001 per share: • Series X 1 non-voting convertible preferred stock, 515,000 shares designated; 110,086 shares and 117,970 shares issued and outstand ing at December 31, 2023 and 2022, respectively; and • Series X non-voting convertible preferred stock, 10,000 shares designated; 4,422 shares and 6,204 shares issued and outstanding at December 31, 2023 and 2022, respectively. Each share of the Series X 1 or X non-voting convertible preferred stock (the “Preferred Stock”) is convertible into 55.5556 shares of common stock, at the option of the holder at any time, subject to certain limitations, including, that the holder will be prohibited from converting the Preferred Stock into common stock if, as a result of such conversion, the holder, together with its affiliates, would beneficially own a number of shares of common stock above a conversion blocker, which is initially set at 9.99 % or 9.9 % of the total common stock then issued and outstanding immediately following the conversion of such shares of Series X Preferred Stock or Series X 1 Preferred Stock, respectively. The holder of the Preferred Stock is entitled to receive dividends on shares of the Preferred Stock equal (on an as-if-converted-to-common-stock basis and without regard to any beneficial ownership limitations) to and in the same form as dividends actually paid on shares of the common stock. No other dividends will be paid on shares of the Preferred Stock. In the event of any liquidation, dissolution or winding up, the holder of the Preferred Stock will be entitled to receive out of the assets, whether capital or surplus, the same amount that a holder of common stock would receive if the Preferred Stock were fully converted to common stock, which amounts shall be paid pari passu with all holders of common stock. Shares of the Preferred Stock will generally have no voting rights, except as required by law and except that the consent of a majority of the holders of either series of outstanding Preferred Stock will be required to amend the terms of the such series. 2021 Equity Distribution Agreement On March 31, 2021, the Company filed a registration statement on Form S-3 containing a prospectus and prospectus supplement (the "Prospectus") under which the Company may offer and sell up to $ 75.0 million in shares of its common stock, from time to time, pursuant to an open market sale agreement with Jefferies LLC and by any method deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933 (the “ATM Program”). Pursuant to the “baby shelf rules” promulgated by the SEC, if the Company’s public float is less than $ 75.0 million as of specified measurement periods, the number of shares of common stock that may be offered and sold by the Company under a Form S-3 registration statement, including pursuant to the ATM Program, in any twelve-month period is limited to an aggregate amount that does not exceed one-third of the Company’s public float. As of December 31, 2023 , due to the SEC’s “baby shelf rules,” the Company was permitted to sell up to $ 12.3 million of shares of common stock pursuant to the ATM Program. The Company will remain subject to the “baby shelf rules” under the Form S-3 registration statement until such time as its public float exceeds $ 75.0 million. During the years ended December 31, 2023 and 2022 , no shares were sold under the Prospectus. This Form S-3 registration statement pursuant to which the ATM Program is registered will expire in May 2024, and no shares of common stock may be sold under the ATM Program after that date. 2021 Warrant Exchange Agreement On September 21, 2021, the Company issued warrants exercisable for 298,692 shares of common stock in exchange for warrants exercisable for 5,376.456 shares of Series X 1 Non-Voting Convertible Preferred Stock previously issued as part of the Anelixis merger. These Series X 1 Non-Voting Convertible Preferred Stock warrants were replaced by Eledon for the outstanding warrants issued by Anelixis that were not settled upon completion of the merger. 2022 Exchange Agreement On January 11, 2022, the Company entered into an exchange agreement (the “Series X 1 Exchange Agreement”) with Biotechnology Value Fund, L.P., Biotechnology Value Fund II, L.P., Biotechnology Value Trading Fund OS, L.P., MSI BVF SPV, L.L.C. (collectively, the “BVF Exchanging Stockholders”), pursuant to which the Series X 1 Exchanging Stockholders exchanged (the “Series X 1 Exchange”) 550,000 shares of the Company’s common stock for 9,899.99 shares of Series X 1 Non-Voting Convertible Preferred Stock. 2023 Securities Purchase Agreement On April 28, 2023, the Company entered into the Securities Purchase Agreement with Purchasers, pursuant to which the Company agreed to issue and sell to the Purchasers in the Private Placement (i) in an initial closing, (a) an aggregate of 15,151,518 shares (the “Shares”) of the Company’s common stock, $ 0.001 par value per share, or pre-funded warrants in lieu thereof (the “Pre-Funded Warrants”), and (b) common stock warrants exercisable into an aggregate of 15,151,518 shares of common stock (or Pre-Funded Warrants in lieu thereof) (the “Common Warrants” and, together with the Pre-Funded Warrants, the “Warrants”); (ii) in a second closing, upon the satisfaction of specified conditions set forth in the Securities Purchase Agreement, an aggregate of 20,202,024 shares of common stock (or Pre-Funded Warrants); and (iii) in a third closing, upon the satisfaction of specified conditions set forth in the Securities Purchase Agreement, an aggregate of 25,252,530 shares of common stock (or Pre-Funded Warrants), in each case subject to customary adjustments as provided in the Securities Purchase Agreement, Pre-Funded Warrant or Common Warrant, as applicable. Each Common Warrant has an exercise price of $ 3.00 per share and expires five years after issuance. The Pre-Funded Warrants are exercisable immediately and until exercised in full, with an exercise price of $ 0.001 per share . The Shares, the Warrants, and the shares of common stock issuable upon the exercise of the Warrants, have not been registered under the Securities Act of 1933, as amended, and were offered pursuant to the exemption from registration provided in Section 4(a)(2) under the Securities Act of 1933, as amended, and Rule 506(b) promulgated thereunder. On May 5, 2023, the initial closing occurred and the Company received $ 35.0 million, or net proceeds of approximately $ 33.0 million after deducting offering costs, in exchange for 8,730,168 shares of common stock and Pre-Funded Warrants to purchase 6,421,350 shares of common stock. The Company may receive an additional $ 105.0 million upon sale of the shares to be issued in the second and third closings, subject to achieving specified clinical development milestones and volume weighted average share price levels and trading volume conditions, and an additional $ 45.5 million assuming the exercise of all Common Warrants issued in the initial closing of the Private Placement. In connection with the Private Placement, the Company filed on May 18, 2023, a registration statement on Form S-3 (“Registration Statement”) with the SEC to register for resale the Shares and the shares of common stock issuable upon the exercise of the Warrants. The Registration Statement became effective on June 2, 2023. 2023 Conversion Agreement of Non-Voting Convertible Preferred Stock On May 16, 2023, Cormorant Global Healthcare Master Fund LP provided notice to convert (i) 1,782 shares of Series X Non-Voting Convertible Preferred Stock for 99,000 shares of common stock in accordance with the Certificate of Designation of Preferences, Rights and Limitations of the Series X Non-Voting Convertible Preferred Stock, and (ii) 7,883.586 shares of Series X 1 Non-Voting Convertible Preferred Stock for 437,977 shares of common stock in accordance with the Certificate of Designation of Preferences, Rights and Limitations of the Series X 1 Non-Voting Convertible Preferred Stock. The conversion was completed on May 23, 2023. 2023 Exercise of Pre-Funded Warrants On July 10, 2023, Armistice Capital Master Fund Ltd. (the “Exercising Stockholder”), exercised Pre-Funded Warrants to purchase 501,197 shares of common stock at an exercise price of $ 0.001 per share, which were issued in conjunction with the Securities Purchase Agreement. On July 14, 2023, the Company issued 501,197 shares of common stock to the Exercising Stockholder in accordance with such exercise. On November 2, 2023, Armistice Capital Master Fund Ltd. (the “Exercising Stockholder”), exercised Pre-Funded Warrants to purchase 653,000 shares of common stock at an exercise price of $ 0.001 per share, which were issued in conjunction with the Securities Purchase Agreement. On November 6, 2023, the Company issued 653,000 shares of common stock to the Exercising Stockholder in accordance with such exercise. Common Stock Warrants As of December 31, 2023 , 21,564,302 warrants were exercisable into common stock (after rounding for fractional shares and subject to beneficial ownership conversion blockers). The following table shows the warrants to purchase common stock activity: Roll Forward of Warrant Activity Private placement warrants Pre-funded warrants Warrants exchanged for Series X 1 preferred stock Total Balance as of December 31, 2022 337,822 509,117 298,692 1,145,631 Issued 15,151,518 6,421,350 — 21,572,868 Exercised — ( 1,154,197 ) — ( 1,154,197 ) Cancelled/Expired — — — — Balance as of December 31, 2023 15,489,340 5,776,270 298,692 21,564,302 Preferred Stock Warrants As of December 31, 2023 , there were 50,207.419 warrants exercisable into Series X 1 Preferred Stock which are convertible into 2,789,301 shares of common stock (after rounding for fractional shares and subject to beneficial ownership conversion blockers). Roll Forward of Series X 1 Convertible Preferred Warrant Activity Total Balance as of December 31, 2022 50,207.419 Assumed and replaced — Exercised — Cancelled/Expired — Balance as of December 31, 2023 50,207.419

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Note 11. Stock-Based Compensation Stock Option Plans On June 21, 2023, the Company held its Annual Meeting of Stockholders (the “Annual Meeting”). At the Annual Meeting, the Company’s stockholders approved an amendment to the Company’s 2020 Long Term Incentive Plan (the “2020 Plan”). The 2020 Plan, as amended, (i) reflects an increase in the limit on the aggregate number of shares of the Company’s common stock that may be delivered pursuant to all awards granted under the 2020 Incentive Plan by an additional 9,600,000 shares so that the new aggregate share limit under the 2020 Plan is 14,460,000 shares, and (ii) extends the date through which the Company may grant new awards under the 2020 Plan from November 15, 2030 to April 26, 2033. In 2023, the Company issued stock option awards to its employees with both time-based and performance-based vesting requirements totaling 7,381,857 stock options, with 1,476,372 of the granted stock options subject to the Company’s customary time-based vesting schedule. The remaining 5,905,485 stock options granted are subje ct to both customary time-based vesting requirements and performance-based vesting requirements that are based on the same clinical development milestones applicable to the second and third closings of the Private Placement as specified in the Securities Purchase Agreement. Further, for the performance-based stock options granted to senior management, upon such second and third closing, a full or prorated amount of each closing shall vest based on the percentage of funding received relative to the total funding opportunity represented by the purchasers' second and third closing subscription amounts. No specified clinical development milestones were achieved during the year ended December 31, 2023. The 2014 Plan was closed to new grants following the approval of the 2020 Plan, and therefore, there were no shares reserved for issuance under the 2014 Plan as of December 31, 2023 . The number of shares reserved for issuance under the 2020 Plan and ESPP was 3,093,742 and 24,077 shares, respectively, as of December 31, 2023. The following table summarizes all option activity under the 2007 Plan, 2014 Plan, 2020 Plan and inducement grants: Shares Weighted Weighted Aggregate (In years) Outstanding as of January 1, 2022 4,213,977 $ 10.33 8.4 $ — Granted 1,267,700 3.81 — — Forfeited / Canceled ( 263,644 ) 12.12 — — Outstanding as of December 31, 2022 5,218,033 $ 8.69 8.1 $ — Granted 11,026,451 2.10 — — Forfeited / Canceled ( 862,631 ) 8.07 — — Outstanding as of December 31, 2023 15,381,853 $ 4.21 8.9 $ 235 Options vested and expected to vest as of 9,476,369 $ 5.40 8.2 $ 235 Options exercisable as of December 31, 2023 4,065,023 $ 8.54 7.0 $ — Intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that had exercise prices that were lower than the fair value per share of the common stock on the date of exercise. There was no aggregate intrinsic value of options exercised during the year ended December 31, 2023. The Company estimates the fair value of stock option awards on the grant date using the Black-Scholes option pricing model with the following weighted-average assumptions: Year Ended 2023 2022 Expected stock price volatility 90.5 % 83.9 % Risk-free interest rate 3.7 % 2.0 % Expected life of options 6.08 years 6.27 years Estimated dividend yield 0 % 0 % The per share weighted average grant date fair value of stock options granted during the years ended December 31, 2023 and 2022 wa s $ 1.60 and $ 2.76 , r espectively. Restricted Stock Units The following table shows the RSU activity, as follows: Shares Weighted (In years) Outstanding as of January 1, 2022 20,000 $ 5.07 Granted 15,000 2.47 RSUs Vested ( 20,000 ) 5.07 Forfeited / Canceled — — Outstanding as of December 31, 2022 15,000 $ 2.47 Granted — — RSUs Vested ( 15,000 ) 2.47 Forfeited / Canceled — — Outstanding as of December 31, 2023 — $ — Stock-based Compensation Expense Total compensation expense related to all of the Company’s stock-based awards for the years ended December 31, 2023 and 2022 was comprised of the following (in thousands): Year Ended 2023 2022 Stock-based compensation classified as: Research and development expense $ 1,491 $ 3,230 General and administrative expense 5,054 4,923 Total stock-based compensation expense $ 6,545 $ 8,153 As of December 31, 2023 , total unrecognized stock-based compensation expense related to non-vested equity awards was $ 12.4 million, which is expected to be recognized over an estimated weighted-average period of 2.4 years.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Note 12. Subsequent Events On January 30, 2024, Armistice Capital Master Fund Ltd. (the “Exercising Stockholder”), exercised Pre-Funded Warrants to purchase 600,000 shares of common stock at an exercise price of $ 0.001 per share, which were issued in conjunction with the Securities Purchase Agreement. On January 30, 2024, the Company issued 600,000 shares of common stock to the Exercising Stockholder in accordance with such exercise.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The consolidated financial statements are prepared in accordance with GAAP. Eledon, a Delaware corporation, owns 100 % of the issued and outstanding common stock or other ownership interest in Anelixis Therapeutics, LLC, a Delaware limited liability company, and Otic Pharma, Ltd., a private limited company organized under the laws of the State of Israel (“Otic”). Otic owns 100 % of the issued and outstanding common stock or other ownership interest in its U.S. subsidiary, Otic Pharma, Inc. The functional currency of the Company’s foreign subsidiary is the U.S. Dollar; however, certain expenses, assets and liabilities are transacted at the local currency. These transactions are translated from the local currency into U.S. Dollars at exchange rates during or at the end of the reporting period. The activities of the Company’s foreign subsidiary are not significant to the consolidated financial statements. All significant intercompany accounts and transactions among the entities have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make informed estimates and assumptions that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to stock-based compensation, accruals for liabilities, impairment of long-lived assets, and other matters that affect the consolidated financial statements and related disclosures. Actual results could differ materially from those estimates under different assumptions or conditions and the differences may be material to the consolidated financial statements.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consists of cash, cash equivalents and short-term investments. The Company maintains deposits in federally insured institutions in excess of federally insured limits and invests in short-term investments with the primary objective of seeking to preserve principal, achieve liquidity requirements and safeguard invested funds. We believe that the Company is not exposed to significant credit risk due to the financial position of the depository institution in which those deposits are held and the nature, including the credit ratings, of our cash equivalents and short-term investments, but we have not eliminated all credit risk.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking accounts, money market funds, U.S. government securities and U.S. government agency securities. Cash and cash equivalents are valued at cost, which approximates their fair value due to the short-term maturities of these investments.
Risks and Uncertianties	Risks and Uncertainties As of December 31, 2023 and 2022, all of the Company’s long-lived assets were located in the United States. The Company’s products will require approval from the U.S. Food and Drug Administration (“FDA”) and foreign regulatory agencies before commercial sales can commence. There can be no assurance that its products will receive any of these required approvals. The denial or delay of such approvals may impact the Company’s business in the future. In addition, after the approval by the FDA, there is still an ongoing risk of adverse events that did not appear during the product approval process. The Company is subject to risks common to companies in the pharmaceutical industry, including, but not limited to, new technological innovations, clinical development risk, establishment of appropriate commercial partnerships, protection of proprietary technology, compliance with government and environmental regulations, uncertainty of market acceptance of products, product liability, the volatility of its stock price and the need to obtain additional financing. The Company's facilities and equipment, including those of the Company's suppliers and vendors, may be affected by natural or man-made disasters. The Company's administrative office is based in Irvine, California and the Company manages all its research and development activities through third parties that are located throughout the world. The Company has taken precautions to safeguard its facilities, equipment and systems, including insurance, health and safety protocols, and off-site storage of computer data. However, the Company's facilities and systems, as well as those of its third-party suppliers and vendors, may be vulnerable to earthquakes, fire, storm, public health or similar emergencies, power loss, telecommunications failures, physical and software break-ins, software viruses and similar events which could cause substantial delays in its operations, damage or destroy its equipment or inventory, and cause the Company to incur additional expenses and delay research and development activities. In addition, the insurance coverage the Company maintains may not be adequate to cover its losses in any circumstance and may not continue to be available to use on acceptable terms, or at all.
Reportable Segments	Reportable Segments Operating segments under GAAP are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the Chief Operating Decision Maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance. The CODM is the Company’s Chief Executive Officer and the Company has determined that it operates in one business segment, which is the development of products for therapeutic medicines selectively targeting critical pathways associated with the underlying molecular pathogenesis for patients with severe inflammation and autoimmune diseases.
Goodwill	Goodwill Goodwill represents the difference between the consideration transferred and the fair value of the net assets acquired under the acquisition method of accounting. Goodwill is not amortized but is evaluated for impairment as of December 31 of each year or if indicators of impairment exist that would, more likely than not, reduce the fair value from its carrying amount. The Company performs its goodwill impairment analysis at the reporting unit level, which aligns with the Company’s reporting structure and availability of discrete financial information. The Company performs its annual impairment analysis by either comparing the reporting unit’s estimated fair value to its carrying amount or doing a qualitative assessment of a reporting unit’s fair value from the last quantitative assessment to determine if there is potential impairment. The Company may do a qualitative assessment when the results of the previous quantitative test indicated the reporting unit’s estimated fair value was significantly in excess of the carrying value of its net assets and it does not believe there have been significant changes in the reporting unit’s operations that would significantly decrease its estimated fair value or significantly increase its net assets. If a quantitative assessment is performed, the evaluation includes management estimates of cash flow projections based on internal future projections and/or use of a market approach by looking at market values of comparable companies. Key assumptions for these projections include revenue growth, future gross and operating margin growth, and its weighted cost of capital and terminal growth rates. The revenue and margin growth is based on increased sales of new products as the Company maintains investments in research and development. Additional assumed value creators may include increased efficiencies from capital spending. The resulting cash flows are discounted using a weighted average cost of capital. Operating mechanisms and requirements to ensure that growth and efficiency assumptions will ultimately be realized are also considered in the evaluation, including timing and probability of regulatory approvals for Company products to be commercialized. The Company’s market capitalization is also considered as a part of its analysis. The Company’s annual evaluation for impairment of goodwill consists of one reporting unit. In accordance with the Company’s policy, the Company completed its annual evaluation for impairment using the quantitative assessment, utilizing the market approach and due to declining market conditions, determined that the fair value of the reporting unit was below its carrying value. As a result, the Company recognized $ 48.6 million of goodwill impairment, reducing the goodwill balance to zero for the year ended December 31, 2022, and accordingly, no goodwill impairment was recorded for the year ended December 31, 2023.
Long-Lived Assets	Long-Lived Assets Property and equipment are recorded at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Additions, major renewals and improvements are capitalized and repair and maintenance costs are charged to expense as incurred. Leasehold improvements are amortized over the remaining life of the initial lease term or the estimated useful lives of the assets, whichever is shorter. The Company reviews property and equipment for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. An impairment loss would be recognized when estimated future undiscounted cash flows relating to the asset are less than its carrying amount. An impairment loss is measured as the amount by which the carrying amount of an asset exceeds its fair value. Significant management judgment is required in the forecast of future operating results that are used in the preparation of expected cash flows. No impairments of long-lived assets have been identified during the years presented.
In-Process Research and Development	In-Process Research and Development The fair values of in-process research and development (“IPR&D”) projects acquired in a business combination that are not complete are capitalized and accounted for as indefinite-lived intangible assets until completion or abandonment of the related research and development (“R&D”) efforts. Upon successful completion of the project, the capitalized amount is amortized over its estimated useful life. If a project is abandoned, all remaining capitalized amounts are written off immediately. Major risks and uncertainties are often associated with IPR&D projects because we are required to obtain regulatory approvals before marketing the resulting products. Such approvals require completing clinical trials that demonstrate a product candidate is safe and effective. Consequently, the eventual realized value of the acquired IPR&D project may vary from its fair value at the date of acquisition, and IPR&D impairment charges may occur in future periods. Capitalized IPR&D projects are tested for impairment annually and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. We consider various factors for potential impairment, including the current legal and regulatory environment and the competitive landscape. Adverse clinical trial results, significant delays in obtaining marketing approval, the inability to bring a product to market and the introduction or advancement of competitors’ products could result in partial or full impairment of the related intangible assets.
Research and Development Expenses	Research and Development Expenses Research and development expenses include personnel and facility-related expenses, outside contracted services including clinical trial costs, manufacturing and process development costs, research costs and other consulting services and non-cash stock-based compensation. Research and development costs are expensed as incurred. Amounts due under contracts with third parties may be either fixed fee or fee for service, and may include upfront payments, monthly payments and payments upon the completion of milestones or receipt of deliverables. Non-refundable advance payments under agreements are capitalized and expensed as the related goods are delivered or services are performed. The Company’s contracts with third parties to perform various clinical trial activities in the on-going development of potential products. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows to its vendors. Payments under the contracts depend on factors such as the achievement of certain events, successful enrollment of patients, and completion of portions of the clinical trial or similar conditions. The Company’s accrual for clinical trials is based on estimates of the services received and efforts expended pursuant to contracts with clinical trial centers and clinical research organizations. These contracts may be terminated by the Company upon written notice and the Company is generally only liable for actual effort expended by the organizations to the date of termination, although in certain instances the Company may be further responsible for termination fees and penalties. The Company estimates its research and development expenses and the related accrual as of each balance sheet date based on the facts and circumstances known to the Company at that time. There have been no material adjustments to the Company’s prior period accrued estimates for clinical trial activities through December 31, 2023 .
Net Loss Per Share	Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, incentive stock options, restricted stock units and warrants are considered to be potentially dilutive securities and are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive. Therefore, basic and diluted net loss per share was the same for the periods presented due to the Company’s net loss position. Basic weighted average shares outstanding for the years ended December 31, 2023 and 2022 include 5,776,270 and 509,117 , respectively, shares underlying pre-funded warrants to purchase common shares. As the shares underlying these pre-funded warrants can be issued for little consideration (an exercise price per share equal to $ 0.001 per share), these shares are deemed to be issued for purposes of basic earnings per share. Year Ended 2023 2022 (In thousands, except share and per share data) Net loss $ ( 40,326 ) $ ( 87,966 ) Net loss per share, basic and diluted $ ( 1.64 ) $ ( 6.16 ) Weighted-average number of common shares 24,619,197 14,285,254 The computation of diluted earnings per share excludes incentive stock options, restricted stock units, and warrants that are anti-dilutive. The following table provides a summary as of December 31, 2023 and 2022 common share equivalents that were excluded because their inclusion would have been anti-dilutive. Year Ended 2023 2022 Stock options outstanding and other equity awards 14,909,155 5,012,035 Common and preferred warrants outstanding 18,577,332 3,127,121 Total 33,486,487 8,139,156
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for all stock-based awards based on the grant-date estimated fair value. The fair value of stock options is determined using the Black-Scholes option pricing model, using assumptions which are subjective and require significant judgment and estimation by management. The risk-free rate assumption was based on observed yields from governmental zero-coupon bonds with an equivalent term. The expected volatility assumption was based on historical volatilities of a group of comparable industry companies whose share prices are publicly available. The peer group was developed based on companies in the pharmaceutical industry. The expected term of stock options represents the weighted-average period that the stock options are expected to be outstanding. Because the Company does not have historical exercise behavior, the Company determined the expected life assumption using the simplified method for stock options granted to employees, which is an average of the options ordinary vesting period and the contractual term. The expected dividend assumption was based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not expect to pay dividends at any time in the foreseeable future. The Company recognizes forfeitures on an actual basis and as such did not estimate forfeitures to calculate stock-based compensation. Restricted Stock Units (“RSUs”) are measured and recognized based on the quoted market price of our common stock on the date of grant.
Income Taxes	Income Taxes Significant judgment is required in determining the Company’s provision for income taxes, deferred tax assets and liabilities and the valuation allowance recorded against net deferred tax assets. We assess the likelihood that deferred tax assets will be recovered as deductions from future taxable income. The evaluation of the need for a valuation allowance is performed on a jurisdiction-by-jurisdiction basis and includes a review of all available positive and negative evidence. Factors reviewed include projections of pre-tax book income for the foreseeable future, determination of cumulative pre-tax book income after permanent differences, earnings history, and reliability of forecasting. We have provided a valuation allowance on our deferred tax assets as of December 31, 2023 and 2022 because we believe it is more likely than not that a majority of our deferred tax assets will not be realized as of this date. The Company evaluates the accounting for uncertainty in income tax recognized in its consolidated financial statements and determines whether it is more likely than not that a tax position will be sustained upon examination by the appropriate taxing authorities before any part of the benefit is recorded in its consolidated financial statements. For those tax positions where it is “not more likely than not” that a tax benefit will be sustained, no tax benefit is recognized. Where applicable, associated interest and penalties are also recorded. The Company has not accrued any liabilities for any such uncertain tax positions as of December 31, 2023 and 2022. The Company is subject to U.S. federal and state tax authority examinations for all the years since inception due to net operating loss and tax credit carryforwards. The net operating losses and tax credits are subject to adjustment until the statute closes on the year the attributes are ultimately utilized. The Company’s income tax returns are based on calculations and assumptions that are subject to examination by the Internal Revenue Service and other tax authorities. In addition, the calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax regulations. The Company recognizes liabilities for uncertain tax positions based on a two-step process. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50 % likely of being realized upon settlement. While the Company believes it has appropriate support for the positions taken on its tax returns, the Company regularly assesses the potential outcomes of examinations by tax authorities in determining the adequacy of its provision for income taxes. The Company continually assesses the likelihood and amount of potential revisions and adjusts the income tax provision, income taxes payable and deferred taxes in the period in which the facts that give rise to a revision become known. For additional information, see Note 9. Income Taxes.
Recent Accounting Pronouncements Issued But Not Adopted	Recent Accounting Pronouncements Issued But Not Adopted In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This update requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU No. 2023-09 is effective for public entities with annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This update requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280, on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023 and for interim periods beginning after December 15, 2024, with early adoptions permitted. The Company is currently evaluating the impact of this guidance on its consolidated financial statements. Other recent accounting pronouncements issued by the FASB (including its Emerging Issues Task Force), the American Institute of Certified Public Accountants, and the SEC did not, or are not believed by management to, have a material impact on the Company’s present or future financial position, results of operations or cash flows.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Common Share Equivalents Included from Computation of Net Loss Per Share	As the shares underlying these pre-funded warrants can be issued for little consideration (an exercise price per share equal to $ 0.001 per share), these shares are deemed to be issued for purposes of basic earnings per share. Year Ended 2023 2022 (In thousands, except share and per share data) Net loss $ ( 40,326 ) $ ( 87,966 ) Net loss per share, basic and diluted $ ( 1.64 ) $ ( 6.16 ) Weighted-average number of common shares 24,619,197 14,285,254
Summary of Common Share Equivalents were excluded because the Inclusion is Anti-dilutive	The following table provides a summary as of December 31, 2023 and 2022 common share equivalents that were excluded because their inclusion would have been anti-dilutive. Year Ended 2023 2022 Stock options outstanding and other equity awards 14,909,155 5,012,035 Common and preferred warrants outstanding 18,577,332 3,127,121 Total 33,486,487 8,139,156

Short-Term Investments (Tables)

Short-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Short-term Investments Classified as Available-for-sale Securities	The following is a summary of short-term investments, which were classified as available-for-sale securities as of December 31, 2023: December 31, 2023 Amortized Cost Fair Value U.S. government securities $ 33,213 $ 33,213 U.S. government agency securities 13,277 13,277 Total short-term investments $ 46,490 $ 46,490

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Table Text Block Supplement [Abstract]
Financial Instruments Measured At Fair Value On A Recurring Basis	The following table summarizes the Company's financial instruments measured at fair value on a recurring basis as of December 31, 2023 and 2022. Included within cash and cash equivalents on the consolidated balance sheets, but excluded from the fair value hierarchy table, are cash deposits held at financial institutions. December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 4,246 $ — $ — $ 4,246 Total cash equivalents 4,246 — — 4,246 Short-term investments: U.S. government securities — 33,213 — 33,213 U.S. government agency securities — 13,277 — 13,277 Total short-term investments — 46,490 — 46,490 Total financial assets $ 4,246 $ 46,490 $ — $ 50,736 December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 9,296 $ — $ — $ 9,296 Total cash equivalents 9,296 — — 9,296 Total financial assets $ 9,296 $ — $ — $ 9,296

Prepaid Expenses, Other Asset_2

Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Prepaid Expenses Other Assets Accrued Expenses And Other Liabilities [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following as of December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Prepaid insurance $ 624 $ 823 Prepaid clinical 4,128 2,115 Prepaid other 185 143 Other current assets 90 28 Total prepaid expenses and other current assets $ 5,027 $ 3,109
Schedule of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consisted of the following as of December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Accrued compensation and related expenses $ 2,003 $ 1,909 Accrued clinical 451 1,826 Accrued professional services 47 65 Accrued other 44 112 Total accrued expenses and other liabilities $ 2,545 $ 3,912

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Total Balance as of December 31, 2021 $ 48,648 Impairments ( 48,648 ) Balance as of December 31, 2022 $ — Impairments — Balance as of December 31, 2023 $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Components of Lease Expense	The components of lease expense were as follows (in thousands): Year Ended 2023 2022 Operating lease cost (a) $ 400 $ 403 (a) Includes variable operating lease expenses, which are immaterial.
Schedule of Other Information Related to Leases	Other information related to leases was as follows (in thousands, except lease term and discount rate): Year Ended 2023 2022 Supplemental Cash Flows Information Cash paid for amounts included in the measurement of lease liability: Operating cash flows from operating lease $ 378 $ 387 Operating lease asset obtained in exchange for lease liability: Operating lease $ — $ 344 Remaining lease term Operating lease 0.95 years 1.95 years Discount rate Operating lease 2.49 % 2.49 %
Schedule of Future Payments Under Noncancelable Operating Leases	Future payments under noncancelable operating leases having initial or remaining terms of one year or more are as follows for the succeeding fiscal year and thereafter (in thousands): Year Ended 2023 2024 388 Total minimum lease payments 388 Less imputed interest ( 5 ) Present value of lease liabilities 383 Less current portion of operating lease liability ( 383 ) Non-current operating lease liability $ —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Summary of Loss Before Income Taxes	Loss before income taxes are as follows (in thousands): Year Ended 2023 2022 Losses before income taxes: U.S. $ ( 40,525 ) $ ( 88,159 ) Non-U.S. 199 193 Total $ ( 40,326 ) $ ( 87,966 )
Summary of Provision (Benefit) for Income Taxes	The provision (benefit) for income taxes are as follows (in thousands): Year Ended 2023 2022 Current: Federal $ — $ — State — — Foreign — — — — Deferred: Federal — — State — — Foreign — — — — Provision (benefit) for income taxes $ — $ —
Reconciliation of U.S. Federal Statutory Income Tax Rate	A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows (in thousands): Year Ended 2023 2022 Statutory federal income tax rate $ ( 8,468 ) $ ( 18,473 ) State income taxes, net of federal tax benefits ( 1,097 ) ( 2,678 ) Tax credits ( 972 ) ( 1,046 ) Stock-based compensation 728 986 Permanent items 9 3 State rate differential 32 274 NOL true-up 2 ( 337 ) Other 566 114 Goodwill impairment — 11,697 Change in valuation allowance 9,200 9,460 Total provision for income taxes $ — $ —
Schedule of Significant Components Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2023 and 2022 consisted of the following (in thousands): Year Ended 2023 2022 Net operating loss carryforwards $ 18,089 $ 15,230 Research and development tax credits 3,202 2,294 Accruals and reserves 475 452 Research expenditures 10,567 5,264 Stock-based compensation 3,085 2,874 Depreciation and amortization 1,319 1,595 Lease liability 91 179 Total deferred tax assets 36,828 27,888 Right-of-use asset ( 87 ) ( 178 ) Acquired IPR&D ( 7,682 ) ( 7,787 ) Total deferred tax liabilities ( 7,769 ) ( 7,965 ) Less: valuation allowance ( 30,811 ) ( 21,675 ) Net deferred tax liabilities $ ( 1,752 ) $ ( 1,752 )
Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits	The following table reconciles the beginning and ending amounts of unrecognized tax benefits for the years presented (in thousands): Year Ended 2023 2022 Gross unrecognized tax benefits at the beginning of the year $ 2,664 $ 1,469 Additions from tax positions taken in the current year 972 914 Additions from tax positions taken in prior years — 281 Gross unrecognized tax benefits at the end of the year $ 3,636 $ 2,664

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2023
Common Stock Warrants [Member]
Class Of Stock [Line Items]
Schedule of Warrant Activity	The following table shows the warrants to purchase common stock activity: Roll Forward of Warrant Activity Private placement warrants Pre-funded warrants Warrants exchanged for Series X 1 preferred stock Total Balance as of December 31, 2022 337,822 509,117 298,692 1,145,631 Issued 15,151,518 6,421,350 — 21,572,868 Exercised — ( 1,154,197 ) — ( 1,154,197 ) Cancelled/Expired — — — — Balance as of December 31, 2023 15,489,340 5,776,270 298,692 21,564,302
Preferred Stock Warrants [Member]
Class Of Stock [Line Items]
Schedule of Warrant Activity	As of December 31, 2023 , there were 50,207.419 warrants exercisable into Series X 1 Preferred Stock which are convertible into 2,789,301 shares of common stock (after rounding for fractional shares and subject to beneficial ownership conversion blockers). Roll Forward of Series X 1 Convertible Preferred Warrant Activity Total Balance as of December 31, 2022 50,207.419 Assumed and replaced — Exercised — Cancelled/Expired — Balance as of December 31, 2023 50,207.419

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of All Option Activity Under 2007 Plan, 2014 Plan, 2020 Plan and Inducement Grants	The following table summarizes all option activity under the 2007 Plan, 2014 Plan, 2020 Plan and inducement grants: Shares Weighted Weighted Aggregate (In years) Outstanding as of January 1, 2022 4,213,977 $ 10.33 8.4 $ — Granted 1,267,700 3.81 — — Forfeited / Canceled ( 263,644 ) 12.12 — — Outstanding as of December 31, 2022 5,218,033 $ 8.69 8.1 $ — Granted 11,026,451 2.10 — — Forfeited / Canceled ( 862,631 ) 8.07 — — Outstanding as of December 31, 2023 15,381,853 $ 4.21 8.9 $ 235 Options vested and expected to vest as of 9,476,369 $ 5.40 8.2 $ 235 Options exercisable as of December 31, 2023 4,065,023 $ 8.54 7.0 $ —
Schedule of Assumptions Used in Black-Scholes Option Pricing Model to Determine the Fair Value of Stock Options Granted	The Company estimates the fair value of stock option awards on the grant date using the Black-Scholes option pricing model with the following weighted-average assumptions: Year Ended 2023 2022 Expected stock price volatility 90.5 % 83.9 % Risk-free interest rate 3.7 % 2.0 % Expected life of options 6.08 years 6.27 years Estimated dividend yield 0 % 0 %
Summary of RSU Activity	The following table shows the RSU activity, as follows: Shares Weighted (In years) Outstanding as of January 1, 2022 20,000 $ 5.07 Granted 15,000 2.47 RSUs Vested ( 20,000 ) 5.07 Forfeited / Canceled — — Outstanding as of December 31, 2022 15,000 $ 2.47 Granted — — RSUs Vested ( 15,000 ) 2.47 Forfeited / Canceled — — Outstanding as of December 31, 2023 — $ —
Schedule of Stock-Based Compensation Expense Related to Stock-Based Awards	Total compensation expense related to all of the Company’s stock-based awards for the years ended December 31, 2023 and 2022 was comprised of the following (in thousands): Year Ended 2023 2022 Stock-based compensation classified as: Research and development expense $ 1,491 $ 3,230 General and administrative expense 5,054 4,923 Total stock-based compensation expense $ 6,545 $ 8,153

Description of Business - Addit

Description of Business - Additional Information (Detail)	Sep. 14, 2020
Anelixis [Member]
Description Of Business [Line Items]
Date of acquisition	Sep. 14, 2020

Going Concern and Management'_2

Going Concern and Management's Plans - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	May 05, 2023	Dec. 31, 2023	Dec. 31, 2022	Apr. 28, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net loss		$ (40,326)	$ (87,966)
Accumulated deficit		(243,191)	$ (202,865)
Cash and cash equivalents and short-term investments		$ 51,100
Common stock, shares issued		24,213,130	13,776,788
Securities Purchase Agreement Initial Closing [Member] | Private Placement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common warrants issued	$ 35,000
Securities Purchase Agreement Initial Closing [Member] | Private Placement [Member] | Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, shares issued	6,421,350
Securities Purchase Agreement Initial Closing [Member] | Accredited Investor [Member] | Private Placement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common warrants issued	$ 45,500
Common stock, shares issued	8,730,168			15,151,518
Common stock warrants to purchase common stock shares	15,151,518			15,151,518
Securities Purchase Agreement Second and Third Closing [Member] | Accredited Investor [Member] | Private Placement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common warrants issued	$ 105,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Reporting_Unit Segment $ / shares shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash, cash equivalents and restricted cash, maturity period	three months or less
Number of operating business segments | Segment	1
Number of reporting units | Reporting_Unit	1
Impairment charge	$ 0	$ 48,648,000
Impairments of long-lived assets	0	0
Goodwill	$ 0	$ 0	$ 48,648,000
Basic weighted average shares outstanding | shares	24,619,197	14,285,254
Warrants exercise price | $ / shares	$ 0.001
Tax benefit	$ 0
Income tax examination, likelihood of settlement, description	The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon settlement.
Income tax examination, likelihood of settlement, percentage	50%
Common and Preferred Warrants Outstanding [Member]
Summary Of Significant Accounting Policies [Line Items]
Basic weighted average shares outstanding | shares	5,776,270	509,117
Anelixis [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment charge		$ 48,600,000
Anelixis Therapeutics, LLC and Otic Pharma, Ltd.
Summary Of Significant Accounting Policies [Line Items]
Ownership interest percentage	100%
Otic Pharma, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership interest percentage	100%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Common Share Equivalents Included from Computation of Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Net loss	$ (40,326)	$ (87,966)
Net loss per share, basic	$ (1.64)	$ (6.16)
Net loss per share, diluted	$ (1.64)	$ (6.16)
Weighted-average number of common shares, basic	24,619,197	14,285,254
Weighted-average number of common shares, diluted	24,619,197	14,285,254

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Common Share Equivalents were excluded because the Inclusion is Anti-dilutive (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	33,486,487	8,139,156
Stock Options Outstanding and Other Equity Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	14,909,155	5,012,035
Common and Preferred Warrants Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	18,577,332	3,127,121

Short-Term Investments - Summar

Short-Term Investments - Summary of Short-term Investments Classified as Available-for-sale Securities (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 46,490
Fair Value	46,490
U.S. Government Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	33,213
Fair Value	33,213
U.S. Government Agency Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	13,277
Fair Value	$ 13,277

Short-Term Investments - Additi

Short-Term Investments - Additional Information (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Short-term investments	$ 46,490,000	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Instruments Measured At Fair Value On A Recurring Basis (Detail) - Fair Value, Recurring Member - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 4,246	$ 9,296
Total short-term investments	46,490
Total financial assets	50,736	9,296
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,246	9,296
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	33,213
U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	13,277
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,246	9,296
Total financial assets	4,246	9,296
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,246	$ 9,296
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	46,490
Total financial assets	46,490
Fair Value, Inputs, Level 2 [Member] | U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	33,213
Fair Value, Inputs, Level 2 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	$ 13,277

Prepaid Expenses, Other Asset_3

Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid insurance	$ 624	$ 823
Prepaid clinical	4,128	2,115
Prepaid other	185	143
Other current assets	90	28
Total prepaid expenses and other current assets	$ 5,027	$ 3,109

Prepaid Expenses, Other Asset_4

Prepaid Expenses, Other Assets, Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities and Other Liabilities [Abstract]
Accrued compensation and related expenses	$ 2,003	$ 1,909
Accrued clinical	451	1,826
Accrued professional services	47	65
Accrued other	44	112
Total accrued expenses and other liabilities	$ 2,545	$ 3,912

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill impairment	$ 0	$ 48,648,000
Anelixis [Member]
Goodwill [Line Items]
Goodwill impairment		$ 48,600,000

Goodwill - Schedule of Goodwill

Goodwill - Schedule of Goodwill (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance	$ 0	$ 48,648,000
Impairments	0	(48,648,000)
Ending balance	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)			12 Months Ended
	Aug. 12, 2022	Nov. 04, 2021 ft²	Dec. 31, 2023 USD ($) Milestone	Dec. 31, 2022 USD ($) ft² Milestone	Dec. 31, 2021 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Other Commitments [Line Items]
Rental expense			$ 400,000	$ 400,000
Remaining term of office lease			12 months
Debt outstanding			$ 0
Indemnification obligations amount			0
Contingent liabilities			$ 0	$ 0
ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Fee due for milestones achieved						$ 1,000,000	$ 1,000,000
Common stock issued in lieu of making a cash payment						$ 1,000,000	$ 1,000,000
Number of Milestones Achieved | Milestone			0	0
Remaining milestone payments for first licensed product			$ 6,000,000
Annual License Maintenance Fee			100,000	$ 100,000	$ 100,000
ALS Therapy Development Foundation, Inc. License Agreement [Member] | Achievement of 500 Million Aggregate Sales [Member]
Other Commitments [Line Items]
Reaching of aggregate net sales			500,000,000
Amount of one-time milestone payment			15,000,000
ALS Therapy Development Foundation, Inc. License Agreement [Member] | Achievement of 1 Billion Aggregate Sales [Member]
Other Commitments [Line Items]
Reaching of aggregate net sales			1,000,000,000
Amount of one-time milestone payment			30,000,000
Maximum [Member] | ALS Therapy Development Foundation, Inc. License Agreement [Member]
Other Commitments [Line Items]
Development and regulatory milestone payments			$ 2,500,000
Irvine, California [Member]
Other Commitments [Line Items]
Area of office space | ft²				5,197
Lease expiration date	Dec. 31, 2024
Burlington, Massachusetts [Member]
Other Commitments [Line Items]
Area of office space | ft²		6,138
Lease expiration date		Nov. 20, 2024

Commitments and Contingencies_2

Commitments and Contingencies - Components of Lease Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 400	$ 403

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Other Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash paid for amounts included in the measurement of lease liability:
Operating cash flows from operating lease	$ 378	$ 387
Operating lease asset obtained in exchange for lease liability:
Operating lease		$ 344
Remaining lease term
Operating lease	11 months 12 days	1 year 11 months 12 days
Discount rate
Operating lease	2.49%	2.49%

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Future Payments Under Noncancelable Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
2024	$ 388
Total minimum lease payments	388
Less imputed interest	(5)
Present value of lease liabilities	383
Less current portion of operating lease liability	(383)	$ (363)
Non-current operating lease liability	$ 0	$ 383

Income Taxes - Summary of Loss

Income Taxes - Summary of Loss Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Losses before income taxes:
U.S.	$ (40,525)	$ (88,159)
Non-U.S.	199	193
Loss before income taxes	$ (40,326)	$ (87,966)

Income Taxes - Summary of Provi

Income Taxes - Summary of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred:
Total provision for income taxes	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Federal Income tax rate	21%	21%
Net valuation allowance Increased (decreased)	$ 9,100,000	$ 9,100,000	$ 9,400,000
Research and development tax credit carryforwards for federal and state	$ 3,202,000	2,294,000
Period for which cumulative change in ownership annual use net operating loss and research and development credit carryforwards	3 years
Accrued interest and penalties associated with uncertain tax positions	$ 0	0
Interest or penalties recorded during the year	$ 0	0
Minimum [Member]
Tax Credit Carryforward [Line Items]
Percentage of cumulative change in ownership	50%
Domestic Tax Authority [Member]
Tax Credit Carryforward [Line Items]
Federal net operating loss carryforwards	$ 68,900,000	56,800,000
Net operating loss carryforward expiration period	2035
Federal net operating loss carryforwards, not to expiration	$ 68,000,000
Research and development tax credit carryforwards for federal and state	$ 4,000,000	2,400,000
Research and development tax credit carryforwards expiration period	2036
State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
State net operating loss carryforwards	$ 30,100,000	25,000,000
Research and development tax credit carryforwards for federal and state	$ 1,500,000	1,200,000
Research and development tax credit carryforwards expiration period	2030
Research and development tax credit carryforwards expiration description	As of December 31, 2023 and 2022, the Company has state research and development credit carryforwards or approximately $1.5 million and $1.2 million, respectively, which will begin expiring in 2030 if not utilized
Israeli Tax Authority [Member] | Foreign Country [Member]
Tax Credit Carryforward [Line Items]
Income tax rate				23%
Foreign operating losses carryforwards	$ 7,900,000	$ 7,900,000
California [Member] | State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Net operating loss carryforward expiration period	2035

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	$ (8,468)	$ (18,473)
State income taxes, net of federal tax benefits	(1,097)	(2,678)
Tax credits	(972)	(1,046)
Stock-based compensation	728	986
Permanent items	9	3
State rate differential	32	274
NOL true-up	2	(337)
Other	566	114
Goodwill impairment	0	11,697
Change in valuation allowance	9,200	9,460
Total provision for income taxes	$ 0	$ 0

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Components Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 18,089	$ 15,230
Research and development tax credits	3,202	2,294
Accruals and reserves	475	452
Research expenditures	10,567	5,264
Stock-based compensation	3,085	2,874
Depreciation and amortization	1,319	1,595
Lease liability	91	179
Total deferred tax assets	36,828	27,888
Right-of-use asset	(87)	(178)
Acquired IPR&D	(7,682)	(7,787)
Total deferred tax liabilities	(7,769)	(7,965)
Less: valuation allowance	(30,811)	(21,675)
Net deferred tax liabilities	$ (1,752)	$ (1,752)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits at the beginning of the year	$ 2,664	$ 1,469
Additions from tax positions taken in the current year	972	914
Additions from tax positions taken in prior years	0	281
Gross unrecognized tax benefits at the end of the year	$ 3,636	$ 2,664

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands

12 Months Ended

May 16, 2023

May 05, 2023

Jan. 11, 2022

Sep. 21, 2021

Mar. 31, 2021

Dec. 31, 2023

Dec. 31, 2022

Nov. 06, 2023

Nov. 02, 2023

Jul. 14, 2023

Jul. 10, 2023

Apr. 28, 2023

Class Of Stock [Line Items]

Common stock, shares issued

24,213,130

13,776,788

Common stock, par value

$ 0.001

$ 0.001

Warrant exercise price per share

$ 0.001

Preferred stock, shares authorized

5,000,000

5,000,000

Preferred stock, par value

$ 0.001

$ 0.001

Warrants available for exercise

21,564,302

Proceeds from issuances of common stock and pre-funded warrants, net

$ 33,017

Armistice Capital Master Fund Ltd [Member] | Securities Purchase Agreement [Member]

Class Of Stock [Line Items]

Common stock, shares issued

653,000

501,197

Warrant exercise price per share

$ 0.001

$ 0.001

Number of pre-funded warrants exercised for common stock

653,000

501,197

Series X1 Preferred Stock [Member]

Class Of Stock [Line Items]

Shares of common stock issued upon conversion of each share of preferred stock

2,789,301

Warrants available for exercise

50,207.419

Series X Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Preferred stock, shares authorized

10,000

10,000

Preferred stock, shares issued

4,422

6,204

Preferred stock, shares outstanding

4,422

6,204

Series X1 Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Preferred stock, shares authorized

515,000

515,000

Preferred stock, par value

$ 0.001

$ 0.001

Preferred stock, shares issued

110,086

117,970

Preferred stock, shares outstanding

110,086

117,970

Common Stock [Member]

Class Of Stock [Line Items]

Warrants available for exercise

21,564,302

Common Stock [Member] | September 2021 Warrant Exchange Agreement [Member]

Class Of Stock [Line Items]

Warrants issued

298,692

Common Stock [Member] | Series X Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Shares of common stock issued upon conversion of each share of preferred stock

55.5556

Common Stock [Member] | Series X1 Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Shares of common stock issued upon conversion of each share of preferred stock

55.5556

Common Stock [Member] | Series X1 Non-voting Convertible Preferred Stock [Member] | September 2021 Warrant Exchange Agreement [Member]

Class Of Stock [Line Items]

Warrants exercisable for exchange

5,376.456

Private Placement Warrants [Member]

Class Of Stock [Line Items]

Warrants available for exercise

15,489,340

Private Placement Warrants [Member] | Accredited Investor [Member]

Class Of Stock [Line Items]

Warrant exercise price per share

$ 3

Private Placement Warrants [Member] | Securities Purchase Agreement Initial Closing [Member]

Class Of Stock [Line Items]

Common warrants issued

$ 35,000

Proceeds from issuances of common stock and pre-funded warrants, net

$ 33,000

Private Placement Warrants [Member] | Securities Purchase Agreement Initial Closing [Member] | Accredited Investor [Member]

Class Of Stock [Line Items]

Common stock, shares issued

8,730,168

15,151,518

Common stock, par value

$ 0.001

Common stock warrants exercisable

15,151,518

15,151,518

Common warrants issued

$ 45,500

Private Placement Warrants [Member] | Securities Purchase Agreement Second Closing [Member] | Accredited Investor [Member]

Class Of Stock [Line Items]

Common stock, shares issued

20,202,024

Private Placement Warrants [Member] | Securities Purchase Agreement Second and Third Closing [Member] | Accredited Investor [Member]

Class Of Stock [Line Items]

Common stock, shares issued

25,252,530

Common warrants issued

$ 105,000

Private Placement Warrants [Member] | Common Stock [Member] | Securities Purchase Agreement Initial Closing [Member]

Class Of Stock [Line Items]

Common stock, shares issued

8,730,168

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

Class Of Stock [Line Items]

Warrant exercise price per share

$ 0.001

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

Class Of Stock [Line Items]

Common stock, shares issued

6,421,350

Maximum [Member] | Common Stock [Member] | Series X Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Conversion of preferred stock, conversion blocker, percent

9.99%

Maximum [Member] | Common Stock [Member] | Series X1 Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Conversion of preferred stock, conversion blocker, percent

9.99%

Minimum [Member] | Common Stock [Member] | Series X Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Conversion of preferred stock, conversion blocker, percent

9.90%

Minimum [Member] | Common Stock [Member] | Series X1 Non-voting Convertible Preferred Stock [Member]

Class Of Stock [Line Items]

Conversion of preferred stock, conversion blocker, percent

9.90%

Jefferies LLC [Member] | ATM Program [Member]

Class Of Stock [Line Items]

Common stock number of shares issued

0

0

Equity distribution agreement maximum value of common shares issuable

$ 75,000

Public float minimum balance to be maintained

$ 75,000

Jefferies LLC [Member] | ATM Program [Member] | Common Stock [Member]

Class Of Stock [Line Items]

Common stock number of shares issued

0

Jefferies LLC [Member] | Maximum [Member] | ATM Program [Member]

Class Of Stock [Line Items]

Equity distribution agreement maximum value of common shares issuable

$ 12,300

BVF Exchanging Stockholders [Member] | Series X1 Non-voting Convertible Preferred Stock [Member] | Series X1 Exchange Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares issued

9,899.99

BVF Exchanging Stockholders [Member] | Common Stock [Member] | Series X1 Exchange Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares converted

550,000

Cormorant Global Healthcare Master Fund LP [Member] | Series X Non-voting Convertible Preferred Stock [Member] | Conversion Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares converted

1,782

Cormorant Global Healthcare Master Fund LP [Member] | Series X1 Non-voting Convertible Preferred Stock [Member] | Conversion Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares converted

7,883.586

Cormorant Global Healthcare Master Fund LP [Member] | Common Stock [Member] | Series X Non-voting Convertible Preferred Stock [Member] | Conversion Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares issued

99,000

Cormorant Global Healthcare Master Fund LP [Member] | Common Stock [Member] | Series X1 Non-voting Convertible Preferred Stock [Member] | Conversion Agreement [Member]

Class Of Stock [Line Items]

Conversion of stock, shares issued

437,977

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Warrants to Purchase Common Stock Activity (Detail)	12 Months Ended
	Dec. 31, 2023 shares
Class Of Warrant Or Right [Line Items]
Ending Balance	21,564,302
Private Placement Warrants [Member]
Class Of Warrant Or Right [Line Items]
Ending Balance	15,489,340
Pre-funded Warrants [Member]
Class Of Warrant Or Right [Line Items]
Ending Balance	5,776,270
Warrants Exchanged for Series X1 Preferred Stock [Member]
Class Of Warrant Or Right [Line Items]
Ending Balance	298,692
Common Stock Warrants [Member]
Class Of Warrant Or Right [Line Items]
Beginning Balance	1,145,631
Issued	21,572,868
Exercised	(1,154,197)
Cancelled/Expired	0
Common Stock Warrants [Member] | Private Placement Warrants [Member]
Class Of Warrant Or Right [Line Items]
Beginning Balance	337,822
Issued	15,151,518
Exercised	0
Cancelled/Expired	0
Common Stock Warrants [Member] | Pre-funded Warrants [Member]
Class Of Warrant Or Right [Line Items]
Beginning Balance	509,117
Issued	6,421,350
Exercised	(1,154,197)
Cancelled/Expired	0
Common Stock Warrants [Member] | Warrants Exchanged for Series X1 Preferred Stock [Member]
Class Of Warrant Or Right [Line Items]
Beginning Balance	298,692
Issued	0
Exercised	0
Cancelled/Expired	0

Stockholders' Equity - Schedu_2

Stockholders' Equity - Schedule of Series X1 Convertible Preferred Stock Warrant Activity (Detail)	12 Months Ended
	Dec. 31, 2023 shares
Class Of Warrant Or Right [Line Items]
Ending Balance	21,564,302
Preferred Stock Warrants [Member]
Class Of Warrant Or Right [Line Items]
Beginning Balance	50,207.419
Assumed and replaced	0
Exercised	0
Cancelled/Expired	0
Ending Balance	50,207.419

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)		12 Months Ended
	Jun. 21, 2023 shares	Dec. 31, 2023 USD ($) Milestone $ / shares shares	Dec. 31, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted		11,026,451	1,267,700
Shares weighted average grant date fair valueof stock options granted | $ / shares		$ 1.6	$ 2.76
Number of specific clinical development milestones achieved | Milestone		0
Aggregate intrinsic value of options exercised | $		$ 0
Unrecognized stock-based compensation expense | $		$ 12,400,000
Unrecognized stock-based compensation expense, recognized over estimated weighted average period		2 years 4 months 24 days
Time Based Vesting Requirements [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted		1,476,372
Time-based and Performance-based Vesting Requirements [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted		7,381,857
Stock options granted		5,905,485
2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, number of shares reserved for issuance		0
2020 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, number of shares reserved for issuance		3,093,742
Increased number of shares	9,600,000
New aggregate share limit	14,460,000
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, number of shares reserved for issuance		24,077

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of All Option Activity Under 2007 Plan, 2014 Plan, 2020 Plan and Inducement Grants (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Shares Issuable Under Options
Outstanding, beginning balance	5,218,033	4,213,977
Granted	11,026,451	1,267,700
Forfeited / Canceled	(862,631)	(263,644)
Outstanding, ending balance	15,381,853	5,218,033	4,213,977
Options vested and expected to vest	9,476,369
Options exercisable	4,065,023
Weighted Average Exercise Price
Outstanding, beginning balance	$ 8.69	$ 10.33
Granted	2.10	3.81
Forfeited / Canceled	8.07	12.12
Outstanding, ending balance	4.21	$ 8.69	$ 10.33
Options vested and expected to vest	5.40
Options exercisable	$ 8.54
Weighted Average Remaining Contractual Term (In years)
Outstanding, balance	8 years 10 months 24 days	8 years 1 month 6 days	8 years 4 months 24 days
Options vested and expected to vest	8 years 2 months 12 days
Options exercisable	7 years
Aggregate Intrinsic Value
Aggregate intrinsic value, Outstanding	$ 235
Options vested and expected to vest	235
Options exercisable	$ 0

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Assumptions Used in Black-Scholes Option Pricing Model to Determine the Fair Value of Stock Options Granted (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Expected stock price volatility	90.50%	83.90%
Risk-free interest rate	3.70%	2%
Expected life of option (in years)	6 years 29 days	6 years 3 months 7 days
Estimated dividend yield	0%	0%

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSU Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Shares Issuable Under RSUs
Options exercisable	4,065,023
Weighted Average Exercise Price
Options exercisable	$ 8.54
RSU [Member]
Shares Issuable Under RSUs
Outstanding, beginning balance	15,000	20,000
Granted		15,000
RSUs Vested	(15,000)	(20,000)
Outstanding, ending balance	0	15,000
Weighted Average Exercise Price
Outstanding, beginning balance	$ 2.47	$ 5.07
Granted		2.47
RSUs Vested	2.47	5.07
Outstanding, ending balance	$ 0	$ 2.47

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense Related to Stock-Based Awards (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,545	$ 8,153
Research and Development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,491	3,230
General and Administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5,054	$ 4,923

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - $ / shares	Jan. 30, 2024	Dec. 31, 2023	Nov. 06, 2023	Nov. 02, 2023	Jul. 14, 2023	Jul. 10, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Warrants exercise price		$ 0.001
Common stock, shares issued		24,213,130					13,776,788
Armistice Capital Master Fund Ltd [Member] | Securities Purchase Agreement [Member]
Subsequent Event [Line Items]
Number of pre-funded warrants exercised for common stock				653,000		501,197
Warrants exercise price				$ 0.001		$ 0.001
Common stock, shares issued			653,000		501,197
Subsequent Event [Member] | Armistice Capital Master Fund Ltd [Member] | Securities Purchase Agreement [Member]
Subsequent Event [Line Items]
Number of pre-funded warrants exercised for common stock	600,000
Warrants exercise price	$ 0.001
Common stock, shares issued	600,000