Vaccinex (VCNX) 10-Q 15 May 24 2024 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 10, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Current Reporting Status	Yes
Trading Symbol	VCNX
Entity Registrant Name	Vaccinex, Inc.
Entity Central Index Key	0001205922
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		1,584,300
Entity File Number	001-38624
Entity Tax Identification Number	16-1603202
Entity Address, Address Line One	1895 Mount Hope Avenue
Entity Address, City or Town	Rochester
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	14620
City Area Code	585
Local Phone Number	271-2700
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 2,972,000	$ 1,535,000
Accounts receivable	2,775,000	961,000
Prepaid expenses and other current assets	1,312,000	853,000
Derivative asset	95,000
Total current assets	7,154,000	3,349,000
Property and equipment, net	110,000	136,000
Operating lease right-of-use asset	103,000	146,000
TOTAL ASSETS	7,367,000	3,631,000
Current liabilities:
Accounts payable	2,329,000	2,039,000
Accrued expenses	1,880,000	1,242,000
Deferred revenue	59,000	63,000
Current portion of long-term debt	76,000	75,000
Operating lease liability	103,000	146,000
Warrant liability	259,000	2,351,000
Total current liabilities	4,706,000	5,916,000
Long-term debt	6,000	26,000
TOTAL LIABILITIES	4,712,000	5,942,000
Commitments and contingencies (Note 6)
Stockholders’ equity (deficit):
Convertible preferred stock (Series A), par value of $0.001 per share; 10,000,000 shares authorized, 10 shares issued and outstanding as of March 31, 2024, and no shares authorized, issued or outstanding as of December 31, 2023; with aggregate liquidation preference of $1,750,000 and $0 as of March 31, 2024 and December 31, 2023, respectively	1,236,000	0
Common stock, par value of $0.0001 per share; 100,000,000 shares authorized as of March 31, 2024, and December 31, 2023; 1,584,305 and 892,622 shares issued as of March 31, 2024 and December 31, 2023, respectively;1,584,300 and 892,617 shares outstanding as of March 31, 2024 and December 31, 2023, respectively	1,000	0
Additional paid-in capital	345,253,000	337,627,000
Treasury stock, at cost; 5 shares of common stock as of March 31, 2024 and December 31, 2023, respectively	(11,000)	(11,000)
Accumulated deficit	(343,824,000)	(339,927,000)
TOTAL STOCKHOLDERS' EQUITY/(DEFICIT)	2,655,000	(2,311,000)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 7,367,000	$ 3,631,000

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Convertible preferred stock (Series A), par value	$ 0.001	$ 0.001
Convertible preferred stock (Series A), authorized	10,000,000	0
Convertible preferred stock (Series A), issued	10	0
Convertible preferred stock (Series A), outstanding	10	0
Convertible preferred stock (Series A), aggregate liquidation preference	$ 1,750,000	$ 0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	1,584,305	892,622
Common stock, shares outstanding	1,584,300	892,617
Treasury stock, common shares	5	5

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 104,000	$ 550,000
Costs and expenses:
Research and development	3,383,000	3,812,000
General and administrative	1,795,000	1,724,000
Total costs and expenses	5,178,000	5,536,000
Loss from operations	(5,074,000)	(4,986,000)
Financing costs - warrant liabilities	(28,000)
Change in fair value of warrant liabilities	1,206,000	0
Other income (expense), net	(1,000)	24,000
Loss before provision for income taxes	(3,897,000)	(4,962,000)
Provision for income taxes	0	0
Net loss attributable to Vaccinex, Inc. common stockholders	(3,897,000)	(4,962,000)
Comprehensive loss	$ (3,897,000)	$ (4,962,000)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic	$ (2.94)	$ (20.89)
Net loss per share attributable to Vaccinex, Inc. common stockholders, diluted	$ (2.94)	$ (20.89)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic	1,327,257	237,527
Weighted-average shares used in computing net loss per share attributable toVaccinex, Inc. common stockholders, diluted	1,327,257	237,527

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Private Placement Offerings	Private Placement Offerings Common Stock	Private Placement Offerings Additional Paid-in Capital	As Amended	As Amended Additional Paid-in Capital	ADDF	ADDF Preferred Stock	ADDF Additional Paid-in Capital
Balance at Dec. 31, 2022	$ 5,193	$ 0	$ 0	$ 324,880	$ (11)	$ (319,676)
Balance, Shares at Dec. 31, 2022		0	237,532		5
Issuance of Common Shares	2,040			2,040
Issuance of Common Shares, Shares			23,693
Stock-based compensation	129			129
Net loss	(4,962)					(4,962)
Balance at Mar. 31, 2023	2,400	$ 0	$ 0	327,049	$ (11)	(324,638)
Balance, Shares at Mar. 31, 2023		0	261,225		5
Balance at Dec. 31, 2023	(2,311)	$ 0	$ 0	337,627	$ (11)	(339,927)
Balance, Shares at Dec. 31, 2023		0	892,622		5
Issuance of Common Shares	2			2
Issuance of Common Shares, Shares			64,816
Stock-based compensation	96			96
Issuance of common stock and pre-funded warrants							$ 4,224	$ 1	$ 4,223
Issuance of common stock and pre-funded warrants, Shares								626,867
Issuance of warrants							$ 750		$ 750			$ 556		$ 556
Issuance of preferred stock												$ 1,236	$ 1,236
Issuance of preferred stock, Shares													10
Reclassification of public warrants, as amended	1,199			1,199
Reclassification of private placement warrants										$ 800	$ 800
Net loss	(3,897)					(3,897)
Balance at Mar. 31, 2024	$ 2,655	$ 1,236	$ 1	$ 345,253	$ (11)	$ (343,824)
Balance, Shares at Mar. 31, 2024		10	1,584,305		5

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (3,897,000)	$ (4,962,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	27,000	31,000
Stock-based compensation	96,000	129,000
Change in fair value of warrant liability	(1,206,000)	0
Changes in operating assets and liabilities:
Accounts receivable	(64,000)	175,000
Prepaid expenses and other current assets	(459,000)	(183,000)
Accounts payable	290,000	(425,000)
Accrued expenses	585,000	195,000
Deferred revenue	(4,000)
Net cash used in operating activities	(4,632,000)	(5,040,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	0	(49,000)
Net cash used in investing activities	0	(49,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, and pre-funded warrants in private placement offerings	2,529,000
Proceeds from issuance of warrants in private placement offerings	1,113,000
Proceeds from private offering of common stock		2,040,000
Payments of long-term debt	(19,000)	(19,000)
Proceeds from issuance of common stock, and private placement warrants	2,446,000
Net cash provided by financing activities	6,069,000	2,021,000
NET INCREASE/(DECREASE) IN CASH AND CASH EQUIVALENTS	1,437,000	(3,068,000)
CASH AND CASH EQUIVALENTS–Beginning of period	1,535,000	6,391,000
CASH AND CASH EQUIVALENTS–End of period	2,972,000	$ 3,323,000
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Issuance of preferred stock included in Accounts Receivable	1,141,000
Issuance of private placement warrants included in Accounts Receivable	556,000
Issuance costs of preferred stock and private placement warrants included in Accrued expenses	$ (53,000)

Company and Nature of Business

Company and Nature of Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Company and Nature of Business	Note 1. COMPANY AND NATURE OF BUSINESS Vaccinex, Inc. (the “Company”) was incorporated in Delaware in April 2001 and is headquartered in Rochester, New York. The Company is a clinical-stage biotechnology company engaged in the discovery and development of targeted biotherapeutics to treat serious diseases and conditions with unmet medical needs, including neurodegenerative diseases, cancer, and autoimmune disorders. Since its inception, the Company has devoted substantially all of its efforts toward product research, manufacturing and clinical development, and raising capital. The Company is subject to a number of risks and uncertainties common to other early-stage biotechnology companies including, but not limited to, dependency on the successful development and commercialization of its product candidates, rapid technological change and competition, dependence on key personnel and collaborative partners, uncertainty of protection of proprietary technology and patents, clinical trial uncertainty, fluctuation in operating results and financial performance, the need to obtain additional funding, compliance with governmental regulations, technological and medical risks, management of growth and effectiveness of marketing by the Company. If the Company does not successfully commercialize or partner any of its product candidates, it will be unable to generate product revenue or achieve profitability. Going Concern These condensed financial statements have been prepared in accordance with generally accepted accounting principles applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has incurred significant losses and negative cash flows from operations since inception and expects to incur additional losses until such a time it can generate significant revenue from the commercialization of its product candidates. The Company reported cash used in operations of $ 4.6 million for the three months ended March 31, 2024, and an accumulated deficit of $ 343.8 million as of March 31, 2024. Given the Company’s projected operating requirements and its existing cash and cash equivalents, the Company is projecting insufficient liquidity to sustain its operations and meet its obligations through one year following the date that the condensed financial statements are issued. These conditions and events raise substantial doubt about the Company’s ability to continue as a going concern. In response to these conditions, management is currently evaluating different strategies to obtain the required funding of future operations. Financing strategies may include, but are not limited to, the public or private sale of equity, debt financing or funds from other capital sources, such as government funding, collaborations, strategic alliances, divestment of non-core assets, or licensing arrangements with third parties. There can be no assurances that the Company will be able to secure additional financing, or if available, that it will be sufficient to meet its needs or on favorable terms. Because management’s plans have not yet been finalized and are not within the Company’s control, the implementation of such plans cannot be considered probable. As a result, the Company has concluded that management’s plans do not alleviate substantial doubt about the Company’s ability to continue as a going concern. The condensed financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Consolidation The accompanying unaudited condensed financial statements reflect the accounts and operations of the Company and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information (Accounting Standards Codification (“ASC”) 270, Interim Reporting) and with the instructions to Form 10-Q and Article 8 of Regulation S-X. Accordingly, these financial statements do not include all of the information necessary for a full presentation of financial position, results of operations, and cash flows in conformity with GAAP. In the opinion of management, the condensed financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the results of the Company for the periods presented. These condensed financial statements should be read in conjunction with the Company’s audited financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on April 2, 2024. Common Stock Reverse Splits On September 25, 2023, the Company effected a 1-for- 15 reverse stock split of its issued shares of common stock. On February 19, 2024, the Company effected a second reverse split of shares of the Company's common stock on a 1-for- 14 basis. All per share amounts, common shares outstanding, warrants, and stock-based compensation amounts for all periods presented have been retroactively adjusted to reflect these reverse stock splits. The shares of common stock retain a par value of $ 0.0001 per share. Use of Estimates These condensed financial statements have been prepared in conformity with U.S. GAAP. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the condensed financial statements and the reported amount of expenses during the reporting period. Such management estimates include those relating to assumptions used in the valuation of stock option awards, valuation of the warrant liabilities, valuation of the derivative asset, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates. Convertible Preferred Stock In March 2024, the Company issued shares of a newly designated series of convertible preferred stock (see Note 9). The convertible preferred stock contained embedded redemption features requiring bifurcation and separate accounting apart from the convertible preferred stock host instrument. The Company recorded the fair value of the embedded redemption features as a derivative asset on the Company’s balance sheets in accordance with ASC Topic 815, Derivatives and Hedging. See Note 4 for the key inputs used in the fair value measurements of the derivative asset. Fair Value of Financial Instruments Financial instruments consist of cash, accounts receivable, derivative asset, accounts payable, accrued liabilities, long-term debt, warrant liabilities, and convertible preferred stock. Cash, accounts receivable, accounts payable, accrued liabilities, debt,and convertible preferred stock are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date of such amounts. Warrant liabilities and the derivative asset are measured at fair value on a recurring basis with the assumptions discussed in Note 4. Concentration of Credit Risk, Other Risks and Uncertainties The Company is subject to a number of risks, including, but not limited to, the lack of available capital; the possible delisting of our common stock from Nasdaq; possible failure of preclinical testing or clinical trials; inability to obtain regulatory approval of product candidates; competitors developing new technological innovations; potential interruptions in the manufacturing and commercial supply operations; unsuccessful commercialization strategy and launch plans for its proprietary drug candidates; risks inherent in litigation, including purported class actions; market acceptance of the Company’s products; and protection of proprietary technology. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash equivalents are deposited in interest-bearing money market accounts. Although the Company deposits its cash with multiple financial institutions, cash balances may occasionally be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company has historically raised capital in transactions with investors that include members of its board of directors and entities controlled by certain board members. As such, the Company's directors, directly and indirectly, control a significant ownership percentage of the Company. The Company can provide no assurances that future financing will be available in sufficient amounts or on terms acceptable to it or that its directors or entities controlled by certain board members will be willing or able to participate in future capital raises by the Company. The Company depends on third-party manufacturers for the manufacture of drug substances and drug product for clinical trials. The Company also relies on certain third parties for its supply chain. Disputes with these third- party manufacturers or shortages in goods or services from third-party suppliers could delay the manufacturing of the Company’s product candidates and adversely impact its results of operations. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 requires disclosure of additional categories of information about federal, state and foreign income taxes in the rate reconciliation table and more details about the reconciling items in some categories if items meet a quantitative threshold. The ASU requires entities to disclose income taxes paid, net of refunds, disaggregated by federal (national), state and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold. The guidance makes several other changes to the disclosure requirements. The ASU is required to be applied prospectively, with the option to apply it retrospectively. The ASU is effective for fiscal years beginning after December 15, 2024. The Company is currently assessing the impact of the adoption of this guidance on its financial statements and disclosures. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. ASU 2023-07 improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the ASU enhances interim disclosure requirements, clarifies circumstances in which an entity can disclose multiple segment measures of profit or loss, and contains other disclosure requirements. The ASU does not change how an entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. The ASU is required to be applied retrospectively to all periods presented in the financial statements. The ASU is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. The Company is currently assessing the impact of the adoption of this guidance on its financial statements and disclosures.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Note 3. BALANCE SHEET COMPONENTS Property and Equipment Property and equipment consist of the following (in thousands): As of As of Leasehold improvements $ 3,277 $ 3,277 Research equipment 3,351 3,351 Furniture and fixtures 350 350 Computer equipment 250 250 Property and equipment, gross 7,228 7,228 Less: accumulated depreciation and amortization ( 7,118 ) ( 7,091 ) Property and equipment, net $ 110 $ 136 Depreciation expense related to property and equipment was $ 27,000 and $ 31,000 for the three months ended March 31, 2024 and 2023, respectively. Accrued Expenses Accrued expenses consist of the following (in thousands): As of As of Accrued clinical trial cost $ 1,128 $ 853 Accrued payroll and related benefits 301 295 Accrued consulting and legal 411 58 Accrued other 40 36 Accrued expenses $ 1,880 $ 1,242

Fair Value Measurements of Fina

Fair Value Measurements of Financial Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements of Financial Measurements	Note 4. FAIR VALUE MEASUREMENTS OF FINANCIAL MEASUREMENTS Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Assets and liabilities recorded at fair value on a nonrecurring basis in the condensed balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Financial instruments consist of cash, accounts receivable, accounts payable, accrued liabilities, long-term debt, and convertible preferred stock. Cash, accounts receivable, accounts payable, accrued liabilities, debt, and convertible preferred stock are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date of such amounts. Assets and Liabilities Measured at Fair Value on a Recurring Basis Fair value measurement standards also apply to certain financial assets and liabilities that are measured at fair value on a recurring basis (each reporting period). For the Company, these financial assets and liabilities include its cash equivalents deposited in money market funds, warrant liabilities, and the derivative asset. The Company does not have any nonfinancial assets or liabilities that are measured at fair value on a recurring basis. The assets’ or liabilities’ fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy (in thousands): As of March 31, 2024 Fair Value Level 1 Level 2 Level 3 Financial Assets: Money market fund $ 12 $ 12 $ - $ - Derivative asset 95 - - 95 Total Financial Assets $ 107 $ 12 $ - $ 95 As of December 31, 2023 Fair Value Level 1 Level 2 Level 3 Financial Assets: Money market fund $ 1,337 $ 1,337 $ - $ - Total Financial Assets $ 1,337 $ 1,337 $ - $ - As of March 31, 2024 Fair Value Level 1 Level 2 Level 3 Financial Liabilities: Warrant liabilities - public warrants $ 237 $ - $ - $ 237 Warrant liabilities - private placement warrants 22 - - 22 Total Financial Liabilities $ 259 $ - $ - $ 259 As of December 31, 2023 Fair Value Level 1 Level 2 Level 3 Financial Liabilities: Warrant liabilities - public warrants $ 2,275 $ - $ - $ 2,275 Warrant liabilities - private placement warrants 76 - - 76 Total Financial Liabilities $ 2,351 $ - $ - $ 2,351 The Company did no t transfer any assets or liabilities measured at fair value on a recurring basis to or from Level 1, Level 2 , and Level 3 during either of the three months ended March 31, 2024 and 2023. Fair Value Measurement of Warrant Liabilities The Company uses the Black-Scholes pricing model to determine the fair value of its warrant liabilities using Level 3 inputs. Inputs used to determine estimated fair value of the warrant liabilities include the fair value of the underlying stock at the valuation date, the term of the warrants, and the expected volatility of the underlying stock. The significant unobservable input used in the fair value measurement of the warrant liabilities is the estimated term of the warrants. The key inputs into the respective valuation models used to estimate the fair value of the warrant liabilities at March 31, 2024, were as follows: Public Warrants Private Placement Warrants Low High Low High Risk-free interest rate 3.81 % 5.30 % 3.81 % 5.30 % Volatility 106 % 130 % 105 % 130 % Dividend yield 0 % 0 % 0 % 0 % Expected term (years) 0.51 4.76 0.51 5.01 Share price $ 7.410 $ 9.310 $ 7.410 $ 9.310 The key inputs into the respective valuation models used to estimate the fair value of the warrant liabilities at December 31, 2023, were as follows: Public Warrants Private Placement Warrants Low High Low High Risk-free interest rate 3.81 % 5.42 % 3.81 % 5.33 % Volatility 99 % 113 % 102 % 113 % Dividend yield 0 % 0 % 0 % 0 % Expected term (years) 0.75 5.01 0.75 5.01 Share price $ 9.310 $ 13.160 $ 9.310 $ 12.880 The following table summarizes the changes in fair value of the Company’s warrant liabilities that is recognized in the change in fair value of the warrant liabilities in the accompanying condensed statements of operations and comprehensive loss during the three months ended March 31, 2024 (in thousands): Public Warrants Private Placement Warrants Total Warrant liabilities as of January 1, 2024 $ 2,275 $ 76 $ 2,351 Issuance of warrants - 1,113 1,113 Reclassified as equity ( 1,199 ) ( 800 ) ( 1,999 ) Change in fair value ( 839 ) ( 367 ) ( 1,206 ) Warrant liabilities as of March 31, 2024 $ 237 $ 22 $ 259 There were no warrant liabilities reported in the Company's condensed balance sheet at March 31, 2023 or change in fair value of warrant liabilities in the accompanying condensed statements of operations and comprehensive loss during the three months ended March 31, 2023.

Collaboration Agreements

Collaboration Agreements	3 Months Ended
	Mar. 31, 2024
Collaboration Agreements [Abstract]
Collaboration Agreements	Note 5. COLLABORATION AGREEMENTS Surface Oncology, Inc. In November 2017, the Company entered into a research collaboration and license option agreement with Surface Oncology, Inc. (“Surface”) to identify and select antibodies against two target antigens, using the Company’s proprietary technology as described in the agreement. Under the agreement, Surface may purchase exclusive options, exercisable by providing a written notice to the Company, to obtain (i) an exclusive product license to make, use, sell and import products incorporating antibodies targeting the first antigen and (ii) an exclusive research tool license to use antibodies targeting the second antigen to perform research. Surface purchased the first option and exercised the second option and we entered into an exclusive research tool license agreement with Surface in the third quarter of 2019. Under the research collaboration and license option agreement, Surface paid an upfront technology access fee of $ 250,000 and makes milestone payments upon completion of each of four designated milestones for the first target antigen specified in the agreement. For the second target antigen, Surface is obligated to make payments to the Company based on time incurred by the Company in the conduct of the work plan described in the agreement. Surface is required to reimburse the Company for expenses incurred (i) in the conduct of the work plan as detailed in the research funding budget and (ii) for patent filings and prosecution of the Company’s program intellectual property as described in the agreement. The exercise of each option would also entail a license fee and annual maintenance fees, and in the case of the product license, royalties and additional milestone payments. This agreement will expire upon the latest of the expiration of both research programs and all evaluation and testing periods. During the three months ended March 31, 2023, the Company recorded $ 500,000 of revenue for achievement of a milestone event. In 2023 Surface terminated this exclusive research license agreement, for the first target, and therefore will not be required to pay the maintenance fee any longer. Surface Oncology has sublicensed this program for the second target to Coherus which is actively continuing phase 1/2 development. Coherus is now responsible for the maintenance fee.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 6. COMMITMENTS AND CONTINGENCIES Nasdaq Deficiency Notice On April 11, 2024, the Company received a letter from the Listing Qualifications staff of Nasdaq notifying the Company that based on the financial statements contained in its Form 10-K for the year-ended December 31, 2023, it no longer complies with the requirement under Nasdaq Listing Rule 5550(b)(1) to maintain a minimum of $ 2.5 million in stockholders’ equity for continued listing on the Nasdaq Capital Market (the “Equity Standard”) or the alternative requirements of having a market value of listed securities of $ 35.0 million or net income from continuing operations of $ 500,000 in the most recently completed fiscal year or two of the last three most recently completed fiscal years (the “Alternative Standards”), and may be subject to delisting. The notification letter had no immediate effect on the Company’s listing on the Nasdaq Capital Market. Nasdaq provided the Company until May 13, 2024, to submit a plan to regain compliance with the Equity Standard (the “Compliance Plan”). The Company timely submitted a Compliance Plan to Nasdaq to regain compliance with the Equity Standard. While there is no certainty we will be granted additional time, we may receive a compliance period, typically of no more than 180 days, to regain compliance with the Equity Standard. Other Contingencies The Company is subject to claims and assessments from time to time in the ordinary course of business. The Company records a provision for a liability when it believes that it is both probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. In the normal course of business, the Company may become involved in legal proceedings. The Company will accrue a liability for such matters when it is probable that a liability has been incurred and the amount can be reasonably estimated. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. The accrual for a litigation loss contingency might include, for example, estimates of potential damages, outside legal fees and other directly related costs expected to be incurred. As of March 31, 2024 and December 31, 2023 the Company was not involved in any material legal proceedings.

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	Note 7. LEASES The Company leases its facilities from 1895 Management, Ltd., a New York corporation controlled by an entity affiliated with a director of the Company, under non-cancellable operating leases. Following entry into a lease extension agreement in August 2022, the lease agreement requires monthly rental payments of $ 15,048 through October 31, 2024. The Company is responsible for all maintenance, utilities, insurance and taxes related to the facility. The Company has elected the practical expedient on not separating lease components from non-lease components. The Company accounts for its leases under ASC 842, Leases. Leases with an initial term of 12 months or less are not recorded on the condensed balance sheet. The Company determines if an arrangement is a lease at inception. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and lease liabilities are recognized based on the present value of lease payments over the lease term. The leases do not provide an implicit rate so in determining the present value of lease payments, the Company uses its incremental borrowing rate for the applicable lease, which was 7.0 %. The Company recognizes lease expense on a straight-line basis over the remaining lease term. As of March 31, 2024, the future minimum payments for the operating leases total $ 105,337 , less imputed interest of $ 2,415 , for an operating lease liability of $ 102,922 . For the three months ended March 31, 2024 and 2023, cash paid for amounts included in the measurement of lease liabilities was $ 45,144 and $ 45,144 , respectively. Lease expense incurred under the operating lease for the three month periods ended March 31, 2024 and 2023 was $ 45,144 and $ 45,144 respectively. Lease expense is a component of general and administrative expense.

Long-term Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2024
Debt Instruments [Abstract]
Long-term Debt	Note 8. LONG-TERM DEBT On May 8, 2020, the Company received a loan under the Small Business Administration's Paycheck Protection Program (the "PPP Loan") in the amount of $ 1,133,600 . The PPP Loan originally matured on May 8, 2022 , with no principal payments required prior to the maturity date, and bearing interest at an annual rate of 1.0 %, with interest payments commencing on November 8, 2020 , less the amount of any potential forgiveness. On November 8, 2021, the Company was awarded loan forgiveness of $ 876,171 and the remaining balance of the loan was refinanced. The loan has a maturity date of May 8, 2025 , bears interest of 1 %, and is being repaid in monthly payments of $ 6,334 . The Company has recorded interest expense of $ 248 and $ 423 for the three month periods ended March 31, 2024 and 2023, respectively, on its condensed statements of operations and comprehensive loss.

Convertible Preferred Stock

Convertible Preferred Stock	3 Months Ended
	Mar. 31, 2024
Class of Stock Disclosures [Abstract]
Convertible Preferred Stock [Text Block]	Note 9. CONVERTIBLE PREFERRED STOCK On March 28, 2024, the Company entered into a securities purchase agreement with the Alzheimer’s Drug Discovery Foundation pursuant to which the Company sold shares of a newly designated series of convertible preferred stock, the Series A Preferred Stock, and warrants to purchase up to 229,057 shares of the Company’s common stock (“ADDF Warrants”) for an aggregate purchase price of $ 1.75 million. Our Series A Preferred Stock is convertible at the election of the holder at any time after the public announcement by the Company of top-line data from its SIGNAL-AD Alzheimer’s disease study (the “Data Release”) into shares of common stock at a conversion price equal to the greater of (a) $ 7.77 per share of common stock and (b)(i) the volume weighted average price of the common stock for the last three trading days prior to delivery of the conversion notice if the common stock is traded on a trading market or if its prices are reported on OTCQB or OTCQX, (ii) the most recent bid price of the common stock if it is then traded on The Pink Open Market, or (iii) in all other cases the fair market value of the common stock as determined by an independent appraiser, which conversion right is subject to termination on the last full day preceding the proposed effective date for exercise of the Company’s redemption right or the date fixed for redemption upon a Deemed Liquidation Event (generally defined to include certain fundamental transactions involving the company including a merger or sale of substantially all of the Company’s assets) or on a liquidation, dissolution or winding up of the Company. The Series A Preferred Stock is non-voting, has no mandatory redemption , and carries an annual 5 % cumulative dividend, increasing by 2 % each year, which dividend rate shall not exceed 12 %. The Series A Preferred Stock will also participate on an as-converted basis in any regular or special dividends paid to holders of our common stock. In addition, the Series A Preferred Stock has a liquidation preference equal to the greater of (i) $ 175,000 per share, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to the Series A Preferred Stock (the “Original Share Price”), plus any accrued but unpaid dividends thereon, whether or not declared, together with any other dividends declared but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Series A Preferred Stock been converted into common stock immediately prior to such liquidation, dissolution, winding up or Deemed Liquidation Event. The Company also agreed that so long as the Series A Preferred Stock is outstanding, the Company will not, without the written consent of the holders of 50.1 % of the Series A Preferred Stock, (i) amend, alter, or repeal any provision of the Company’s certificate of incorporation or bylaws in a manner adverse to the Series A Preferred Stock or (ii) until March 29, 2026, incur any indebtedness for borrowed money in excess of $ 1.0 million. The Company has the right to redeem the Series A Preferred Stock at a price equal to the Original Share Price per share at any time after a public announcement of an increase in pepinemab-treated patients relative to placebo-treated patients, with statistical significance having a p-value of less than or equal to 0.05 , in the change of the FDG-PET standard uptake value ratio for brain metabolism between baseline and month 12 as assessed by [18F]fluorodeoxyglucose (FDG)-PET in the resting state following administration of 40 mg/kg pepinemab or placebo, as applicable, as described in the protocol for the Company’s SIGNAL-AD Alzheimer’s disease study and the associated Statistical Analysis Plan, provided that (i) the holder is not in possession of any material nonpublic information that was provided by the Company or any of its directors, directors, employees, agents, or affiliates and (ii) there is an effective resale registration statement on file covering the underlying common stock. The Series A Preferred Stock have similar characteristics of an “Increasing Rate Security” as described by SEC Staff Accounting Bulletin Topic 5Q, Increasing Rate Preferred Stock. As a result, the discount on Series A Preferred Stock is considered an unstated dividend cost that is amortized over the period preceding commencement of the perpetual dividend using the effective interest method, by charging imputed dividend cost against retained earnings, or additional paid in capital in the absence of retained earnings and increasing the carrying amount of the Series A Preferred Stock by a corresponding amount. The discount of approximately $ 0.48 million is therefore being amortized over four years using the effective yield method. The amortization in each period is the amount which, together with the stated dividend in the period, results in a constant rate of effective cost with regard to the carrying amount of the Series A Preferred Stock. Each share of Series A Preferred Stock contains redemption features which allow for the redemption of the Series A Preferred Stock in the event of a voluntary or involuntary liquidation, dissolution, winding up of the Company, or Deemed Liquidation Event, as defined in the certificate of designations (“liquidation events”). Upon the occurrence of such qualifying liquidation event, the Series A Preferred Stock holder shall be entitled to receive cash or assets of the Company before any distribution or payment may be made to or set apart for the holders of common stock in an amount per share of Series A Preferred Stock equal to, or greater of, (i) $175,000 plus all accrued and unpaid dividends thereon, whether or not declared (the "Liquidation Preference”); or (2) the amount per share the holder would receive if such holder converted the shares of Series A Preferred Stock immediately prior to the date of such payment, with certain additional conditions. The embedded redemption features require the Company to settle the Series A Preferred Stock at the Liquidation Preference amount upon the occurrence of certain qualifying liquidation events, The holder’s exercise of the embedded conversion feature when the volume weighted average price of the Common Stock for the last three trading days is greater than $7.77, as defined in the certificate of designations, settles the Series A Preferred Stock through the issuance of a variable number of Common Stock in a fixed monetary amount of $175,000 per share. As these embedded features provide for settlement in nominal amounts not associated with its underlyings, the embedded features each meet the definition of a derivative. Under ASC 815, certain contractual terms that meet the accounting definition of a derivative must be accounted for separately from the financial instrument in which they are embedded (Note 2). The Company has concluded that the redemption features and the holder’s option to convert when the volume weighted average price of the Common Stock for the last three trading days is greater than $7.77, as defined in the certificate of designations, constitute embedded derivative and, therefore, require bifurcation from the Series A Preferred Stock. In the event of any liquidation or deemed liquidation event, as defined in the certificate of designations, before any distribution or payment may be made to or set apart for the holders of common stock, the Series A Preferred Stock holder is entitled to receive assets from the Company equal to $ 175,000 plus all accrued and unpaid dividends thereon, whether or not declared, per share for a total liquidation value of $ 1.75 million as of March 31, 2024. These redemption provisions were determined to represent embedded derivatives requiring bifurcation from the Series A Preferred Stock. Upon initial issuance, the Company recorded the fair value of the embedded derivatives in the amount of $ 95 thousand as a derivative asset and premium on the Series A Preferred Stock. The derivative is adjusted to fair value at each reporting period with the change in the fair value recorded in earnings. Each ADDF Warrant has an initial exercise price of $ 7.64 per share, is immediately exercisable, and expires March 29, 2029 . The Company will have the right to “call” the exercise of any portion of a holder’s ADDF Warrants by delivering a call notice to the holder at any time after the Positive Data Release. After delivery of a call notice, the ADDF Warrants will continue to be exercisable. Each ADDF Warrant will be canceled and no longer exercisable to the extent the holder fails to timely exercise the ADDF Warrant for the called portion thereof within 30 trading days following the Company’s issuance of a call notice. The Company evaluated the ADDF Warrants and concluded they met the criteria to be classified within stockholders’ equity within additional paid-in-capital because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company's common stock and (6) meet the equity classification criteria. Accordingly, based upon the relative fair values of the instruments on the date of issuance, the Company allocated approximately $ 0.57 million of the gross proceeds to the ADDF Warrants and $ 1.18 million of the gross proceeds to the Series A Preferred Stock which is net of $ 95 thousand, attributed to the derivative asset. The $ 1.75 million of proceeds are included in accounts receivable on the Company's condensed balance sheet as of March 31, 2024, as the $ 1.75 million of proceeds were received by the Company on April 1, 2024.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2024
Warrants and Rights Note Disclosure [Abstract]
Warrants	Note 10. WARRANTS Public Warrants On October 3, 2023 , the Company sold in a public offering (i) 542,857 shares of the Company’s common stock together with public warrants to purchase up to 542,857 shares of common stock and (ii) in lieu of shares of common stock, pre-funded warrants exercisable for 142,857 shares of common stock together with public warrants to purchase up to 142,857 shares of common stock (the “Offering”). Each public warrant has an initial exercise price equal to $ 14.00 per share. The public warrants are immediately exercisable and expire five years from the date of issuance. The shares of common stock and accompanying public warrants were sold at a combined public offering price of $ 14.00 per share and the accompanying public warrants, and the pre-funded warrants and accompanying public warrants were sold at a combined public offering price of $ 13.99 per pre-funded warrant and accompanying public warrants for aggregate gross proceeds of $ 9.6 million, before deductions for placement agent and offering fees payable by the Company. The public warrants may not be exercised if the aggregate number of common stock beneficially owned by the holder thereof immediately following such exercise would exceed a specified beneficial ownership limitation; provided, however, that a holder may increase or decrease the beneficial ownership limitation by giving 61 days’ notice to the Company, but not to any percentage in excess of 9.99 %. The Company has the right to “call” any portion of a holder’s public warrants by delivering a call notice to the holder within 30 days after Company publicly announces an increase in pepinemab-treated patients relative to placebo-treated patients, with statistical significance having a p-value of less than or equal to 0.05 , in the change of the FDG-PET standard uptake value ratio for brain metabolism between baseline and month 12 as assessed by [18F]fluorodeoxyglucose (FDG)-PET in the resting state following administration of 40 mg/kg pepinemab or placebo, as applicable, as described in the protocol for the Company’s SIGNAL-AD Alzheimer’s disease study and the associated Statistical Analysis Plan (the “Positive Data Release”). After delivery of a call notice, the public warrants will continue to be exercisable. Each public warrant will be canceled and no longer exercisable to the extent the holder fails to timely exercise the public warrant for the called portion thereof within 20 trading days following the Company’s issuance of a call notice. In the event of a fundamental transaction, the public warrants required the Company to make a payment based on a Black-Scholes pricing model valuation, using specific inputs that precluded the instruments from being considered indexed to the Company’s own stock in accordance with ASC 815. The public warrants also contained certain terms that provided for an adjustment in response to the occurrence or nonoccurrence of a specified event that is inconsistent with an implicit assumption in a standard valuation model, which also precluded the instruments from being considered indexed to the Company’s stock in accordance with ASC 815. Therefore, upon issuance, the Company accounted for the public warrants as liabilities, which were recorded at the issuance date fair value of approximately $ 3.5 million. In March 2024, the Company entered into warrant amendment agreements with holders of approximately 83 % of the public warrants issued in the Offering to amend aforementioned terms in the public warrants. The public warrants, as amended, were no longer precluded from being considered indexed to the Company's stock in accordance with ASC 815. As a result, 572,139 of the public warrants, as amended, issued in the Offering were reclassified as equity, based on the guidance provided under ASC 815-40. The public warrants, as amended, were marked to fair value on the amendment date resulting in a gain on change in fair value of warrant liabilities of $ 0.7 million in the Company's condensed statements of operations and comprehensive loss for the three months ended March 31, 2024. In addition, $ 1.2 million of public warrant liabilities were reclassified as equity in the Company's condensed statements of stockholders' equity (deficit) for the three months ended March 31, 2024. As of March 31, 2024, all of the public warrants were outstanding. Private Placement Warrants In November 2023, pursuant to securities purchase agreements entered into with certain investors, the Company issued and sold private placement warrants to purchase 37,694 shares of common stock. Each private placement warrant has a purchase price equal to $ 1.75 per share, subject to proportional adjustments in the event of stock splits, combinations (including reverse stock splits), or similar events. The private placement warrants are immediately exercisable and expire five years from the date of issuance and the Company has the right to “call” any portion of the private placement warrants under the same conditions and terms as the public warrants. The private placement warrants are subject to the same beneficial ownership limitations as the public warrants and the pre-funded warrants. Upon issuance, the private placement warrants were precluded from being considered indexed to the Company’s own stock in accordance with ASC 815. Therefore, at issuance, the private placement warrants were liability-classified and recorded at their respective issuance date fair values. On February 6, 2024 , the Company entered into a securities purchase agreement pursuant to which we issued and sold 274,182 shares of our common stock together with private placement warrants to purchase up to 274,182 shares of common stock and (ii) pre-funded warrants to purchase up to 90,363 shares of common stock together with private placement warrants to purchase up to 90,363 shares of our common stock (the “February 2024 SPA”). Each private placement warrant is immediately exercisable and has an initial exercise price of $ 14.00 per share. The shares of common stock and accompanying private placement warrants were sold at a combined price of $ 10.15 per share and the accompanying private placement warrants, and the pre-funded warrants and accompanying private placement warrants were sold at a combined price of $ 10.1486 per pre-funded warrant and accompanying private placement warrant, for aggregate gross proceeds of approximately $ 3.7 million. The Company has the right to “call” the exercise of any portion of a holder’s private placement warrants by delivering a call notice to the holder within 30 days, in the case of the November private placement warrants, or 120 days in the case of the February private placement warrants, after the Positive Data Release. After delivery of a call notice, the private placement warrants will continue to be exercisable. Each private placement warrant will be canceled and no longer exercisable to the extent the holder fails to timely exercise the private placement warrant for the called portion thereof within 20 trading days, in the case of the November private placement warrants, or 30 trading days in the case of the February private placement warrants, following the Company’s issuance of a call notice, provided that to the extent the exercise of a called portion of a private placement warrant would cause the holder to hold common stock in excess of a specified beneficial ownership limitation, upon exercise of such portion, as set forth in the private placement warrant, instead of shares being issued, the exercise would result in the modification of the terms of such portion to be consistent with the terms of the pre-funded warrant. Upon issuance, the private placement warrants were precluded from being considered indexed to the Company’s own stock in accordance with ASC 815. Therefore, at issuance, the private placement warrants were liability-classified and recorded at their issuance date fair value. In March 2024, the Company entered into warrant amendment agreements with holders of 100 % of the private placement warrants issued in November 2023 and holders of 97 % of the private placement warrants issued in the February 2024 SPA to amend the aforementioned terms in the private placement warrants. As a result, 354,693 of the November 2023 and February 2024 SPA private placement warrants, as amended, were no longer precluded from being considered indexed to the Company's stock in accordance with ASC 815. The Company reclassified $ 0.8 million of the amended private placement warrants, as equity, in the Company's condensed statements of stockholders' equity/deficit for the three months ended March 31, 2024 based on the guidance provided under ASC 815-40. The private placement warrants, as amended, were marked to fair value on the amendment date resulting in a gain on change in fair value of warrant liabilities of $ 0.36 million in the Company's condensed statements of operations and comprehensive loss for the three months ended March 31, 2024. On March 27, 2024, the Company entered into a securities purchase agreement pursuant to which the Company issued and sold 193,000 shares of the Company's common stock in a public offering together with private placement warrants to purchase up to 193,000 shares of common stock in a concurrent private placement at a combined price of $ 7.77 per share and accompanying private placement warrant for an aggregate purchase price of approximately $ 1.5 million. Separately on March 27, 2024, the Company entered into a securities purchase agreement in a different form pursuant to which the Company sold 159,683 shares of common stock and private placement warrants to purchase up to 159,683 shares of common stock in a private placement at a combined price of $ 7.77 per share and accompanying private placement warrant for an aggregate purchase price of approximately $ 1.25 million. The Company evaluated the March 2024 private placement warrants and concluded that they met the criteria to be classified within stockholders’ equity within additional paid-in-capital. These private placement warrants are equity classified because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company's common stock and (6) meet the equity classification criteria. Accordingly, the Company allocated approximately $ 0.84 million of the proceeds remaining (after the allocation of proceeds to the common stock in the amount equal to their issuance date fair value) to the March private placement warrants on a relative fair value basis for recognition in additional paid-in capital on the date of issuance. In connection with the securities purchase agreement with the Alzheimer’s Drug Discovery Foundation, the Company sold ADDF Warrants to purchase up to 229,057 shares of common stock. Each ADDF Warrant has an initial exercise price equal to $ 7.64 per share, subject to proportional adjustments in the event of stock splits, combinations (including reverse stock splits), or similar events. These ADDF Warrants are immediately exercisable and will expire on March 29, 2029 . The Company evaluated the ADDF Warrants and concluded they met the criteria to be classified within stockholders’ equity within additional paid-in-capital. The ADDF Warrants are equity classified because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company's common stock and (6) meet the equity classification criteria. Accordingly, based upon the relative fair values of the instruments on the date of issuance, the Company allocated approximately $ 0.57 million of the gross proceeds to the ADDF Warrants and $ 1.18 million of the gross proceeds to the Series A Preferred Stock which is net of $ 95 thousand, attributed to the derivative asset. As of March 31, 2024, all of the private placement warrants were outstanding. Pre-Funded Warrants In connection with the February 2024 SPA, the Company sold pre-funded warrants exercisable for 90,363 shares of common stock. Each pre-funded warrant has an initial exercise price equal to $ 0.0014 per share, subject to proportional adjustments in the event of stock splits, combinations (including reverse stock splits), or similar events. The pre-funded warrants may be exercised at any time and will not expire until exercised in full. The pre-funded warrants are subject to the same beneficial owner limitations as the private placement warrants. The Company evaluated the pre-funded warrants and concluded that they met the criteria to be classified within stockholders’ equity within additional paid-in-capital. The pre-funded warrants are equity classified because they (1) are freestanding financial instruments that are legally detachable and separately exercisable from the common stock, (2) are immediately exercisable, (3) do not embody an obligation for the Company to repurchase its shares, (4) permit the holder to receive a fixed number of shares of common stock upon exercise, (5) are indexed to the Company's common stock and (6) meet the equity classification criteria. Accordingly, the Company allocated approximately $ 0.9 million of the proceeds remaining (after the allocation of proceeds to the liability-classified private placement warrants in the amount equal to their issuance date fair value) to the pre-funded warrants on a relative fair value basis for recognition in additional paid-in capital on the date of issuance. As of March 31, 2024, all of the pre-funded warrants were outstanding.

Common Stock Reserved For Issua

Common Stock Reserved For Issuance	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Common Stock Reserved For Issuance	Note 11. COMMON STOCK RESERVED FOR ISSUANCE Common stock has been reserved for the following potential future issuance: As of As of Shares underlying outstanding stock options 19,111 14,323 Shares available for future stock option grants 18,570 528 Shares underlying outstanding public warrants 685,714 685,714 Shares underlying outstanding private placement warrants 983,981 37,694 Shares underlying convertible preferred stock-if converted 225,225 - Shares underlying outstanding pre-funded warrants 233,220 142,857 Total shares of common stock reserved 2,165,820 881,116

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Note 12. STOCK-BASED COMPENSATION 2011 Employee Equity Plan In connection with the adoption of the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”) in August 2018, the Company ceased granting stock options under the Company’s 2011 Employee Equity Plan (the “2011 Plan”). However, the 2011 Plan will continue to govern the terms and conditions of the outstanding stock options previously granted thereunder. Any shares of stock related to awards outstanding under the 2011 Plan that terminate by expiration, forfeiture, cancellation, or otherwise without the issuance of such shares will become available for grant under the 2018 Plan. Stock options granted under the 2011 Plan expire in five or ten years from the date of grant. 2018 Omnibus Incentive Plan In August 2018, the Company’s board of directors adopted, and its stockholders approved, the 2018 Plan, which allows for the granting of stock, stock options, and stock appreciation rights awards to employees, advisors and consultants. Stock options granted under the 2018 Plan may be either incentive stock options or non-statutory stock options. Incentive stock options may be granted to employees, advisors and consultants at exercise prices of no less than the fair value of the common stock on the grant date. If at the time of grant, the optionee owns stock representing more than 10 % of the voting power of all classes of stock of the Company, the exercise price must be at least 110 % of the fair value of the common stock on the grant date as determined by the board of directors. Non-statutory stock options may be granted to employees, advisors and consultants at exercise prices of less than the fair market value of a share of common stock on the date the non-statutory stock option is granted but shall under no circumstances be less than adequate consideration as determined by the board of directors for such a share. The vesting period of stock option grants is determined by the board of directors, ranging from zero to eight years . Stock options granted under the 2018 Plan expire in five or ten years from the date of grant. The Company initially reserved 2,024 shares of common stock for issuance, subject to certain adjustments, pursuant to awards under the 2018 Plan. Any shares of common stock related to awards outstanding under the 2011 Plan as of the effective date of the 2018 Plan, which thereafter terminate by expiration, forfeiture, cancellation or otherwise without the issuance of such shares, will be added to, and included in, the number of shares of common stock available for grant under the 2018 Plan. In addition, effective January 1, 2020 and continuing until the expiration of the 2018 Plan, the number of shares of common stock available for issuance under the 2018 Plan will automatically increase annually by 2 % of the total number of issued and outstanding shares of the Company’s common stock as of December 31 of the preceding year or such lesser number as the Company’s board of directors may decide, which may be zero. Accordingly, on January 1, 2024, 17,849 additional shares of common stock became available for issuance under the 2018 Plan. A summary of the Company’s stock option activity and related information is as follows: Stock Weighted- Weighted- Aggregate Balance as of January 1, 2024 14,323 $ 446.93 7.7 $ - Granted 5,365 8.21 10.0 Exercised - - - - Forfeited ( 565 ) 626.18 Expired ( 12 ) 3,129.00 Balance as of March 31, 2024 19,111 $ 316.90 8.2 $ - Exercisable as of March 31, 2024 7,055 $ 712.15 6.3 $ - The weighted-average grant date fair value of stock options granted to employees and directors for the three months ended March 31, 2024 and 2023 was $ 5.70 and $ 60.90 per share, respectively. The aggregate grant date fair value of stock options that vested during the three months ended March 31, 2024 and 2023 was $ 70,586 and $ 121,585 , respectively. The intrinsic value of stock options vested and exercisable and expected to vest and become exercisable is calculated based on the difference between the exercise price and the fair value of the Company’s common stock as of March 31, 2024 and December 31, 2023. The intrinsic value of exercised stock options is the difference between the fair value of the underlying common stock and the exercise price as of the exercise date. As of March 31, 2024 and December 31, 2023, total unrecognized compensation cost related to stock options granted to employees was $ 337,032 and $ 448,511 , respectively, which is expected to be recognized over a weighted-average period of 3.37 and 2.16 years, respectively. The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended March 31, 2024 2023 Expected term (in years) 6.0 6.0 Expected volatility 75 % 75 % Risk-free interest rate 4.2 % 3.9 % Expected dividend yield - % - % Total stock-based compensation expense recognized in the condensed statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended March 31, 2024 2023 Research and development $ 42 $ 51 General and administrative 54 78 Total stock-based compensation expense $ 96 $ 129

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Note 13. INCOME TAXES No provision for income taxes was recorded in either of the three month periods ended March 31, 2024 and 2023. The Company remains in a cumulative loss position with a full valuation allowance recorded against its net deferred income tax assets as of March 31, 2024. The Company evaluates tax positions for recognition using a more-likely-than-not recognition threshold, and those tax positions eligible for recognition are measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon the effective settlement with a taxing authority that has full knowledge of all relevant information. As of March 31, 2024 and December 31, 2023, the Company had no unrecognized income tax benefits that would affect the Company’s effective tax rate if recognized.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	Note 14. NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented as they had an anti-dilutive effect: Three Months Ended March 31, 2024 2023 Options to purchase common stock 14,722 8,196 Public warrants to purchase common stock 685,714 - If-converted common shares from convertible preferred stock 9,900 - Private placement warrants to purchase common stock 275,584 -

Segment and Geographical Inform

Segment and Geographical Information	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Segment and Geographic Information	Note 15. SEGMENT AND GEOGRAPHIC INFORMATION The Company’s chief operating decision maker, its Chief Executive Officer, reviews its operating results on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity, the discovery and development of targeted biotherapeutics to treat serious diseases and conditions with unmet medical needs, and there are no segment managers who are held accountable for operations or operating results. Accordingly, the Company operates in one reportable segment. As of March 31, 2024 and December 31, 2023, all long-lived assets are located in the United States.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Note 16. RELATED PARTY TRANSACTIONS As discussed in Note 7, the Company leases its facility from 1895 Management, Ltd., a New York corporation controlled by an entity affiliated with the Company’s chairman and major stockholder of the Company. Rent expense incurred under the operating lease was $ 45,144 for each of the three month periods ended March 31, 2024 and 2023. On March 30, 2023 , the Company entered into a Stock Purchase Agreement, pursuant to which the Company issued and sold 23,693 shares of its common stock at a purchase price of $ 86.10 per share for aggregate gross proceeds of $ 2.04 million (the "March 2023 Private Placement”). FCMI Parent Co. (“FCMI”), which is controlled by Albert D. Friedberg, the chairman of the Company’s board of directors, and Vaccinex (Rochester) L.L.C., which is majority owned and controlled by Dr. Maurice Zauderer, the Company’s President, Chief Executive Officer, and a member of the Company’s board of directors, purchased 23,229 shares of the Company's common stock for an aggregate purchase price of $ 2.0 million in the March 2023 Private Placement. In addition, FCMI made a binding commitment in the Stock Purchase Agreement to purchase, on or prior to May 15, 2023, up to an additional $ 2.96 million of shares of the Company's common stock, less the aggregate purchase price of securities of the Company other than the shares sold by the Company to investors other than FCMI and its affiliates after the closing and on or prior to May 15, 2023, and subject to the terms and conditions of the Stock Purchase Agreement. On March 27, 2024 , the Company entered into a securities purchase agreement pursuant to which the Company issued and sold 193,000 shares of the Company's common stock in a public offering together with warrants to purchase up to 193,000 shares of common stock in a concurrent private placement at a combined price of $ 7.77 per share and accompanying warrant for an aggregate purchase price of approximately $ 1.5 million. Separately on March 27, 2024, the Company entered into a securities purchase agreement in a different form pursuant to which the Company sold 159,683 shares of common stock and warrants to purchase up to 159,683 shares of common stock in a private placement at a combined price of $ 7.77 per share and accompanying warrant for an aggregate purchase price of approximately $ 1.25 million. FCMI and Vaccinex (Rochester) L.L.C. purchased shares of the Company's common stock and accompanying warrants in the latter transaction. These transactions closed on March 28, 2024.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying unaudited condensed financial statements reflect the accounts and operations of the Company and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information (Accounting Standards Codification (“ASC”) 270, Interim Reporting) and with the instructions to Form 10-Q and Article 8 of Regulation S-X. Accordingly, these financial statements do not include all of the information necessary for a full presentation of financial position, results of operations, and cash flows in conformity with GAAP. In the opinion of management, the condensed financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the results of the Company for the periods presented. These condensed financial statements should be read in conjunction with the Company’s audited financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on April 2, 2024.
Common Stock Reverse Splits	Common Stock Reverse Splits On September 25, 2023, the Company effected a 1-for- 15 reverse stock split of its issued shares of common stock. On February 19, 2024, the Company effected a second reverse split of shares of the Company's common stock on a 1-for- 14 basis. All per share amounts, common shares outstanding, warrants, and stock-based compensation amounts for all periods presented have been retroactively adjusted to reflect these reverse stock splits. The shares of common stock retain a par value of $ 0.0001 per share.
Use of Estimates	Use of Estimates These condensed financial statements have been prepared in conformity with U.S. GAAP. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the condensed financial statements and the reported amount of expenses during the reporting period. Such management estimates include those relating to assumptions used in the valuation of stock option awards, valuation of the warrant liabilities, valuation of the derivative asset, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates.
Convertible Preferred Stock	Convertible Preferred Stock In March 2024, the Company issued shares of a newly designated series of convertible preferred stock (see Note 9). The convertible preferred stock contained embedded redemption features requiring bifurcation and separate accounting apart from the convertible preferred stock host instrument. The Company recorded the fair value of the embedded redemption features as a derivative asset on the Company’s balance sheets in accordance with ASC Topic 815, Derivatives and Hedging. See Note 4 for the key inputs used in the fair value measurements of the derivative asset.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments consist of cash, accounts receivable, derivative asset, accounts payable, accrued liabilities, long-term debt, warrant liabilities, and convertible preferred stock. Cash, accounts receivable, accounts payable, accrued liabilities, debt,and convertible preferred stock are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date of such amounts. Warrant liabilities and the derivative asset are measured at fair value on a recurring basis with the assumptions discussed in Note 4.
Concentration of Credit Risk, Other Risks and Uncertainties	Concentration of Credit Risk, Other Risks and Uncertainties The Company is subject to a number of risks, including, but not limited to, the lack of available capital; the possible delisting of our common stock from Nasdaq; possible failure of preclinical testing or clinical trials; inability to obtain regulatory approval of product candidates; competitors developing new technological innovations; potential interruptions in the manufacturing and commercial supply operations; unsuccessful commercialization strategy and launch plans for its proprietary drug candidates; risks inherent in litigation, including purported class actions; market acceptance of the Company’s products; and protection of proprietary technology. Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash equivalents are deposited in interest-bearing money market accounts. Although the Company deposits its cash with multiple financial institutions, cash balances may occasionally be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company has historically raised capital in transactions with investors that include members of its board of directors and entities controlled by certain board members. As such, the Company's directors, directly and indirectly, control a significant ownership percentage of the Company. The Company can provide no assurances that future financing will be available in sufficient amounts or on terms acceptable to it or that its directors or entities controlled by certain board members will be willing or able to participate in future capital raises by the Company. The Company depends on third-party manufacturers for the manufacture of drug substances and drug product for clinical trials. The Company also relies on certain third parties for its supply chain. Disputes with these third- party manufacturers or shortages in goods or services from third-party suppliers could delay the manufacturing of the Company’s product candidates and adversely impact its results of operations.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 requires disclosure of additional categories of information about federal, state and foreign income taxes in the rate reconciliation table and more details about the reconciling items in some categories if items meet a quantitative threshold. The ASU requires entities to disclose income taxes paid, net of refunds, disaggregated by federal (national), state and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold. The guidance makes several other changes to the disclosure requirements. The ASU is required to be applied prospectively, with the option to apply it retrospectively. The ASU is effective for fiscal years beginning after December 15, 2024. The Company is currently assessing the impact of the adoption of this guidance on its financial statements and disclosures. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. ASU 2023-07 improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the ASU enhances interim disclosure requirements, clarifies circumstances in which an entity can disclose multiple segment measures of profit or loss, and contains other disclosure requirements. The ASU does not change how an entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. The ASU is required to be applied retrospectively to all periods presented in the financial statements. The ASU is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. The Company is currently assessing the impact of the adoption of this guidance on its financial statements and disclosures.

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): As of As of Leasehold improvements $ 3,277 $ 3,277 Research equipment 3,351 3,351 Furniture and fixtures 350 350 Computer equipment 250 250 Property and equipment, gross 7,228 7,228 Less: accumulated depreciation and amortization ( 7,118 ) ( 7,091 ) Property and equipment, net $ 110 $ 136
Accrued Expenses	Accrued expenses consist of the following (in thousands): As of As of Accrued clinical trial cost $ 1,128 $ 853 Accrued payroll and related benefits 301 295 Accrued consulting and legal 411 58 Accrued other 40 36 Accrued expenses $ 1,880 $ 1,242

Fair Value Measurements of Fi_2

Fair Value Measurements of Financial Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Fair Value of Financial Assets and Liabilities by Level within Fair Value Hierarchy	The following tables set forth the fair value of the Company’s financial assets and liabilities by level within the fair value hierarchy (in thousands): As of March 31, 2024 Fair Value Level 1 Level 2 Level 3 Financial Assets: Money market fund $ 12 $ 12 $ - $ - Derivative asset 95 - - 95 Total Financial Assets $ 107 $ 12 $ - $ 95 As of December 31, 2023 Fair Value Level 1 Level 2 Level 3 Financial Assets: Money market fund $ 1,337 $ 1,337 $ - $ - Total Financial Assets $ 1,337 $ 1,337 $ - $ - As of March 31, 2024 Fair Value Level 1 Level 2 Level 3 Financial Liabilities: Warrant liabilities - public warrants $ 237 $ - $ - $ 237 Warrant liabilities - private placement warrants 22 - - 22 Total Financial Liabilities $ 259 $ - $ - $ 259 As of December 31, 2023 Fair Value Level 1 Level 2 Level 3 Financial Liabilities: Warrant liabilities - public warrants $ 2,275 $ - $ - $ 2,275 Warrant liabilities - private placement warrants 76 - - 76 Total Financial Liabilities $ 2,351 $ - $ - $ 2,351
Summary of Key Inputs into Valuation Models Used to Estimate Fair Value of Warrant Liabilities	The key inputs into the respective valuation models used to estimate the fair value of the warrant liabilities at March 31, 2024, were as follows: Public Warrants Private Placement Warrants Low High Low High Risk-free interest rate 3.81 % 5.30 % 3.81 % 5.30 % Volatility 106 % 130 % 105 % 130 % Dividend yield 0 % 0 % 0 % 0 % Expected term (years) 0.51 4.76 0.51 5.01 Share price $ 7.410 $ 9.310 $ 7.410 $ 9.310 The key inputs into the respective valuation models used to estimate the fair value of the warrant liabilities at December 31, 2023, were as follows: Public Warrants Private Placement Warrants Low High Low High Risk-free interest rate 3.81 % 5.42 % 3.81 % 5.33 % Volatility 99 % 113 % 102 % 113 % Dividend yield 0 % 0 % 0 % 0 % Expected term (years) 0.75 5.01 0.75 5.01 Share price $ 9.310 $ 13.160 $ 9.310 $ 12.880
Summary of Changes in Fair Value of Company's Warrant Liabilities that is Recognized in Change in Fair Value of Warrant Liabilities in Accompanying Statements of Operations and Comprehensive Loss	The following table summarizes the changes in fair value of the Company’s warrant liabilities that is recognized in the change in fair value of the warrant liabilities in the accompanying condensed statements of operations and comprehensive loss during the three months ended March 31, 2024 (in thousands): Public Warrants Private Placement Warrants Total Warrant liabilities as of January 1, 2024 $ 2,275 $ 76 $ 2,351 Issuance of warrants - 1,113 1,113 Reclassified as equity ( 1,199 ) ( 800 ) ( 1,999 ) Change in fair value ( 839 ) ( 367 ) ( 1,206 ) Warrant liabilities as of March 31, 2024 $ 237 $ 22 $ 259
Schedule of Quantitative Information Regarding Measurement Inputs to Estimate the Fair Value of Asset	The following table provides quantitative information regarding measurement inputs used to estimate the fair value of the Level 3 asset at March 31, 2024: Risk-free interest rate 4.97 % Expected volatility 40.00 % Expected term (in years) 1.00 Exercise price (per share) $ 7.77 Number of shares 10
Schedule of Changes in Derivative Assets	The following table presents the changes in the derivative asset during the three months ended March 31, 2024 (in thousands): Derivative asset as of January 1, 2024 $ - Issuance of convertible preferred stock 95 Change in fair value - Derivative asset as of March 31, 2024 $ 95

Common Stock Reserved For Iss_2

Common Stock Reserved For Issuance (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Common Stock Reserved for Potential Future Issuances	Common stock has been reserved for the following potential future issuance: As of As of Shares underlying outstanding stock options 19,111 14,323 Shares available for future stock option grants 18,570 528 Shares underlying outstanding public warrants 685,714 685,714 Shares underlying outstanding private placement warrants 983,981 37,694 Shares underlying convertible preferred stock-if converted 225,225 - Shares underlying outstanding pre-funded warrants 233,220 142,857 Total shares of common stock reserved 2,165,820 881,116

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity and Related Information	A summary of the Company’s stock option activity and related information is as follows: Stock Weighted- Weighted- Aggregate Balance as of January 1, 2024 14,323 $ 446.93 7.7 $ - Granted 5,365 8.21 10.0 Exercised - - - - Forfeited ( 565 ) 626.18 Expired ( 12 ) 3,129.00 Balance as of March 31, 2024 19,111 $ 316.90 8.2 $ - Exercisable as of March 31, 2024 7,055 $ 712.15 6.3 $ -
Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions	The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended March 31, 2024 2023 Expected term (in years) 6.0 6.0 Expected volatility 75 % 75 % Risk-free interest rate 4.2 % 3.9 % Expected dividend yield - % - %
Total Stock-Based Compensation Expense Recognized in Condensed Statements of Operations and Comprehensive Loss	Total stock-based compensation expense recognized in the condensed statements of operations and comprehensive loss is as follows (in thousands): Three Months Ended March 31, 2024 2023 Research and development $ 42 $ 51 General and administrative 54 78 Total stock-based compensation expense $ 96 $ 129

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share as They Had Anti-Dilutive Effect	The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented as they had an anti-dilutive effect: Three Months Ended March 31, 2024 2023 Options to purchase common stock 14,722 8,196 Public warrants to purchase common stock 685,714 - If-converted common shares from convertible preferred stock 9,900 - Private placement warrants to purchase common stock 275,584 -

Company and Nature of Business

Company and Nature of Business - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash used in operations	$ (4,632)	$ (5,040)
Accumulated deficit	$ 343,824		$ 339,927

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)			3 Months Ended
	Feb. 19, 2024 $ / shares	Sep. 25, 2023 $ / shares	Mar. 31, 2024 $ / shares	Dec. 31, 2023 $ / shares
Accounting Policies [Abstract]
Reverse stock splits description			Company effected a 1-for-15 reverse stock split of its issued shares of common stock. On February 19, 2024, the Company effected a second reverse split of shares of the Company's common stock on a 1-for-14 basis. All per share amounts, common shares outstanding, warrants, and stock-based compensation amounts for all periods presented have been retroactively adjusted to reflect these reverse stock splits.
Stock split, conversion ratio	0.14	0.15
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 7,228	$ 7,228
Less: accumulated depreciation and amortization	(7,118)	(7,091)
Property and equipment, net	110	136
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,277	3,277
Research Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,351	3,351
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	350	350
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 250	$ 250

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation	$ 27,000	$ 31,000

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued clinical trial cost	$ 1,128	$ 853
Accrued payroll and related benefits	301	295
Accrued consulting and legal	411	58
Accrued other	40	36
Accrued expenses	$ 1,880	$ 1,242

Fair Value Measurements of Fi_3

Fair Value Measurements of Financial Measurements - Summary of Fair Value of Financial Assets and Liabilities by Level within Fair Value Hierarchy (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Financial Assets:
Derivative asset	$ 95
Financial Liabilities:
Warrant liabilities	259,000	$ 2,351,000
Public Warrants
Financial Liabilities:
Warrant liabilities	237,000	2,275,000
Private Placement Warrants
Financial Liabilities:
Warrant liabilities	22,000	76,000
Fair Value Measurements Recurring
Financial Assets:
Derivative asset	95,000
Total Financial Assets	107,000	1,337,000
Financial Liabilities:
Total Financial Liabilities	259,000	2,351,000
Fair Value Measurements Recurring | Public Warrants
Financial Liabilities:
Warrant liabilities	237,000	2,275,000
Fair Value Measurements Recurring | Private Placement Warrants
Financial Liabilities:
Warrant liabilities	22,000	76,000
Fair Value Measurements Recurring | Money Market Funds
Financial Assets:
Cash equivalents	12,000	1,337,000
Fair Value Measurements Recurring | Level 1
Financial Assets:
Derivative asset	0
Total Financial Assets	95,000	1,337,000
Fair Value Measurements Recurring | Level 1 | Money Market Funds
Financial Assets:
Cash equivalents	12,000	1,337,000
Fair Value Measurements Recurring | Level 3
Financial Assets:
Derivative asset	95,000
Total Financial Assets	12,000
Financial Liabilities:
Total Financial Liabilities	259,000	2,351,000
Fair Value Measurements Recurring | Level 3 | Public Warrants
Financial Liabilities:
Warrant liabilities	237,000	2,275,000
Fair Value Measurements Recurring | Level 3 | Private Placement Warrants
Financial Liabilities:
Warrant liabilities	$ 22,000	$ 76,000

Fair Value Measurements of Fi_4

Fair Value Measurements of Financial Measurements - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrant liabilities	$ 259,000	$ 0	$ 2,351,000
Change in fair value of warrant liabilities	(1,206,000)	0
Fair Value Measurements Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial assets, level 1 to level 2 transfer, amount	0	0
Financial assets, level 2 to level 1 transfer, amount	0	0
Financial assets, transfer in to level 3, amount	0	0
Financial assets, transfer out of level 3, amount	0	0
Financial liabilities, level 1 to level 2 transfer, amount	0	0
Financial liabilities, level 2 to level 1 transfer, amount	0	0
Financial liabilities, transfer in to level 3, amount	0	0
Financial liabilities, transfer out of level 3, amount	$ 0	$ 0

Fair Value Measurements of Fi_5

Fair Value Measurements of Financial Measurements - Summary of Key Inputs in to Valuation Models Used to Estimate Fair Value of Warrant Liabilities (Details)	Mar. 31, 2024	Dec. 31, 2023
Public Warrants | Maximum | Risk-Free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	5.3	5.42
Public Warrants | Maximum | Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	130	113
Public Warrants | Maximum | Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0	0
Public Warrants | Maximum | Expected Term (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	4.76	5.01
Public Warrants | Maximum | Share Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	9.31	13.16
Public Warrants | Minimum | Risk-Free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	3.81	3.81
Public Warrants | Minimum | Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	106	99
Public Warrants | Minimum | Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0	0
Public Warrants | Minimum | Expected Term (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0.51	0.75
Public Warrants | Minimum | Share Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	7.41	9.31
Private Placement Warrants | Maximum | Risk-Free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	5.3	5.33
Private Placement Warrants | Maximum | Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	130	113
Private Placement Warrants | Maximum | Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0	0
Private Placement Warrants | Maximum | Expected Term (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	5.01	5.01
Private Placement Warrants | Maximum | Share Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	9.31	12.88
Private Placement Warrants | Minimum | Risk-Free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	3.81	3.81
Private Placement Warrants | Minimum | Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	105	102
Private Placement Warrants | Minimum | Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0	0
Private Placement Warrants | Minimum | Expected Term (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	0.51	0.75
Private Placement Warrants | Minimum | Share Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities measurement input	7.41	9.31

Fair Value Measurements of Fi_6

Fair Value Measurements of Financial Measurements - Summary of Changes in Fair Value of Company's Warrant Liabilities that is Recognized in Change in Fair Value of Warrant Liabilities in Accompanying Statements of Operations and Comprehensive Loss (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities as of January 1, 2024	$ 2,351,000
Issuance of warrants	1,113,000
Reclassified as equity	(1,999,000)
Change in fair value	(1,206,000)	$ 0
Warrant liabilities as of March 31, 2024	259,000
Public Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities as of January 1, 2024	2,275,000
Reclassified as equity	(1,199,000)
Change in fair value	(839,000)
Warrant liabilities as of March 31, 2024	237,000
Private Placement Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant liabilities as of January 1, 2024	76,000
Issuance of warrants	1,113,000
Reclassified as equity	(800,000)
Change in fair value	(367,000)
Warrant liabilities as of March 31, 2024	$ 22,000

Fair Value Measurements of Fi_7

Fair Value Measurements of Financial Measurements - Schedule of Quantitative Information Regarding Measurement Inputs to Estimate the Fair Value of Asset (Details) - Level 3	Mar. 31, 2024
Risk-Free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset measurement input	4.97
Expected Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset measurement input	40
Expected Term (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset measurement input	1
Exercise Price (per share)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset measurement input	7.77
Number of shares
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset measurement input	10

Fair Value Measurements of Fi_8

Fair Value Measurements of Financial Measurements - Schedule of Changes in Derivative Assets (Details)	3 Months Ended
	Mar. 31, 2024 USD ($)
Fair Value Disclosures [Abstract]
Issuance of convertible preferred stock	$ 95
Derivative assets ending balance	$ 95

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details)	1 Months Ended	3 Months Ended
	Nov. 30, 2017 USD ($) Milestone TargetAntigen	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen	2
Revenue		$ 104,000	$ 550,000
Surface Oncology, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payments fee received	$ 250,000
Number of designated milestones | Milestone	4
Surface Oncology, Inc. | Exclusive Product License
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			$ 500,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Subsequent Event	Apr. 11, 2024 USD ($)
Commitments And Contingencies [Line Items]
Minimum stockholders' equity required for listing	$ 2,500,000
Market value of listed securities	35,000,000
Net income from continuing operations related to listing	$ 500,000

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	3 Months Ended		27 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Oct. 31, 2024
Lessee Lease Description [Line Items]
Lessee operating lease, incremental borrowing rate	7%
Lessee, operating lease, discount rate, description	The leases do not provide an implicit rate so in determining the present value of lease payments, the Company uses its incremental borrowing rate for the applicable lease, which was 7.0%.
Future minimum operating leases payment in total	$ 105,337
Imputed interest	2,415
Operating lease liability	102,922
Cash paid for amount included in measurement of lease liabilities	45,144	$ 45,144
Lease expense incurred under operating lease	$ 45,144	$ 45,144
Forecast
Lessee Lease Description [Line Items]
Monthly rental payments			$ 15,048

Long-term Debt - Additional Inf

Long-term Debt - Additional Information (Details) - PPP Loan - USD ($)			3 Months Ended
	Nov. 08, 2021	May 08, 2020	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Interest expense			$ 248	$ 423
Amount of loan received		$ 1,133,600
Maturity date	May 08, 2025	May 08, 2022
Debt instrument interest rate	1%	1%
Payments commencement date		Nov. 08, 2020
CARES Act of 2020 aid forgiveness amount	$ 876,171
Monthly repayment	$ 6,334

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details)			3 Months Ended
	Apr. 01, 2024 USD ($)	Mar. 28, 2024 USD ($) PValue TradingDay $ / shares shares	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Class of Stock [Line Items]
Accounts receivable			$ 2,775,000	$ 961,000
Liquidation value			1,750,000,000	$ 0
Derivative asset			$ 95
ADDF Warrant
Class of Stock [Line Items]
Warrant expiration date		Mar. 29, 2029	Mar. 29, 2029
Number of trading days | TradingDay		30
Proceeds from issuance of warrants			$ 570,000
Securities Purchase Agreement
Class of Stock [Line Items]
Maximum common stock purchased | shares		229,057
Aggregate purchase price of common stock		$ 1,750,000
Conversion price | $ / shares		$ 7.77
Minimum limit of borrowings		$ 1,000,000
Securities Purchase Agreement | ADDF Warrant
Class of Stock [Line Items]
Exercise price of warrants | $ / shares		$ 7.64
Series A Preferred Stock
Class of Stock [Line Items]
Proceeds from issuance of convertible preferred stock			1,180,000
Discount on preferred stock		$ 480,000
Amortization period of preferred stock		4 years
Preferred stock liquidation asset value			175,000
Liquidation value			1,750,000
Derivative asset		$ 95,000	95,000
Series A Preferred Stock | Securities Purchase Agreement
Class of Stock [Line Items]
Preferred stock, voting rights		The Series A Preferred Stock is non-voting, has no mandatory redemption
Preferred stock, dividend rate		5%
Increase in dividend rate per year		2%
Maximum limit dividend rate can increase		12%
Preferred stock, a liquidation preference | $ / shares		$ 175,000
Percentage of share holders consent required to amend bylaws		50.10%
Series A Preferred Stock | Securities Purchase Agreement | Maximum
Class of Stock [Line Items]
Statistical significance of p-value | PValue		0.05
ADDF Warrants and Series A Preferred Stock
Class of Stock [Line Items]
Accounts receivable			$ 1,750,000
Subsequent Event | ADDF Warrants and Series A Preferred Stock
Class of Stock [Line Items]
Proceeds from issuance of preferred stock and warrants	$ 1,750,000

Warrants - Additional Informati

Warrants - Additional Information (Details)						1 Months Ended		3 Months Ended
	Mar. 28, 2024 USD ($) PValue TradingDay $ / shares	Mar. 27, 2024 $ / shares shares	Feb. 06, 2024 USD ($) TradingDay $ / shares shares	Oct. 03, 2023 USD ($) PValue TradingDay $ / shares shares	Mar. 30, 2023	Feb. 29, 2024 USD ($) $ / shares shares	Nov. 30, 2023 $ / shares shares	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)
Class of Warrant or Right [Line Items]
Sale of stock, transaction date					Mar. 27, 2024
Derivative asset | $								$ 95
Change in fair value of warrant liability | $								(1,206,000)	$ 0
Reclassification of public warrants, as amended | $								$ 1,199,000
Description of public warrants right to call								The Company has the right to “call” any portion of a holder’s public warrants by delivering a call notice to the holder within 30 days after Company publicly announces an increase in pepinemab-treated patients relative to placebo-treated patients, with statistical significance having a p-value of less than or equal to 0.05, in the change of the FDG-PET standard uptake value ratio for brain metabolism between baseline and month 12 as assessed by [18F]fluorodeoxyglucose (FDG)-PET in the resting state following administration of 40 mg/kg pepinemab or placebo, as applicable, as described in the protocol for the Company’s SIGNAL-AD Alzheimer’s disease study and the associated Statistical Analysis Plan (the “Positive Data Release”). After delivery of a call notice, the public warrants will continue to be exercisable. Each public warrant will be canceled and no longer exercisable to the extent the holder fails to timely exercise the public warrant for the called portion thereof within 20 trading days following the Company’s issuance of a call notice.
Series A Preferred Stock
Class of Warrant or Right [Line Items]
Proceeds from issuance of common stock | $								$ 1,180,000
Derivative asset | $	$ 95,000							$ 95,000
Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Shares issued, price per share | $ / shares								$ 7.64
November Warrant Offering
Class of Warrant or Right [Line Items]
Warrants issued								354,693
February 2024 Private Placement
Class of Warrant or Right [Line Items]
Sale of stock, transaction date			Feb. 06, 2024
Warrants issued								354,693
Proceeds from issuance of common stock | $			$ 3,700,000
Public Offering and Private Placement
Class of Warrant or Right [Line Items]
Shares issued, price per share | $ / shares		$ 7.77
Maximum [Member] | Securities Purchase Agreement | Series A Preferred Stock
Class of Warrant or Right [Line Items]
Statistical significance of p-value | PValue	0.05
Common Stock
Class of Warrant or Right [Line Items]
Number of shares sold		159,683
Common Stock | Private Placement
Class of Warrant or Right [Line Items]
Warrants issued		159,683
Common Stock | Public Offering and Private Placement
Class of Warrant or Right [Line Items]
Shares issued, price per share | $ / shares		$ 7.77
Public Warrants
Class of Warrant or Right [Line Items]
Sale of stock, transaction date				Oct. 03, 2023
Warrants expiration period				5 years
Call notice period				30 days
Number of trading days | TradingDay				20
Issuance date fair value | $				$ 3,500,000
Percentage of public warrants issued with holders								83%
Change in fair value of warrant liability | $								$ 700,000
Public Warrants | Maximum [Member]
Class of Warrant or Right [Line Items]
Statistical significance of p-value | PValue				0.05
Public Warrants | Common Stock
Class of Warrant or Right [Line Items]
Number of shares sold		193,000		542,857
Warrants issued				542,857
Shares issued, price per share | $ / shares				$ 14
Notice period to change beneficial ownership limitation				61 days
Maximum beneficial ownership limitation				9.99%
Public Warrants | Warrants Reclassified As Equity
Class of Warrant or Right [Line Items]
Warrants issued								572,139
Reclassification of public warrants, as amended | $								$ 1,200,000
Pre Funded Warrants and Public Warrants
Class of Warrant or Right [Line Items]
Shares issued, price per share | $ / shares				$ 13.99
Proceeds from issuance of common stock | $				$ 9,600,000
Pre Funded Warrants and Public Warrants | Common Stock
Class of Warrant or Right [Line Items]
Warrants issued				142,857
Pre-funded Warrants
Class of Warrant or Right [Line Items]
Proceeds from issuance of common stock | $						$ 900,000
Pre-funded Warrants | Common Stock
Class of Warrant or Right [Line Items]
Number of shares sold						90,363
Warrants issued				142,857
Shares issued, price per share | $ / shares						$ 0.0014
Private Placement Warrants
Class of Warrant or Right [Line Items]
Warrants expiration period							5 years
Proceeds from issuance of common stock | $								$ 840,000
Description of warrants right to call								The Company has the right to “call” the exercise of any portion of a holder’s private placement warrants by delivering a call notice to the holder within 30 days, in the case of the November private placement warrants, or 120 days in the case of the February private placement warrants, after the Positive Data Release. After delivery of a call notice, the private placement warrants will continue to be exercisable. Each private placement warrant will be canceled and no longer exercisable to the extent the holder fails to timely exercise the private placement warrant for the called portion thereof within 20 trading days, in the case of the November private placement warrants, or 30 trading days in the case of the February private placement warrants, following the Company’s issuance of a call notice, provided that to the extent the exercise of a called portion of a private placement warrant would cause the holder to hold common stock in excess of a specified beneficial ownership limitation, upon exercise of such portion, as set forth in the private placement warrant, instead of shares being issued, the exercise would result in the modification of the terms of such portion to be consistent with the terms of the pre-funded warrant.
Change in fair value of warrant liability | $								$ 360,000
Reclassification of public warrants, as amended | $								$ 800,000
Private Placement Warrants | November Warrant Offering
Class of Warrant or Right [Line Items]
Call notice period				30 days
Number of trading days | TradingDay			20
Percentage of warrants issued with holders								100%
Private Placement Warrants | February 2024 Private Placement
Class of Warrant or Right [Line Items]
Call notice period			120 days
Number of trading days | TradingDay			30
Percentage of warrants issued with holders								97%
Private Placement Warrants | Common Stock | November Warrant Offering
Class of Warrant or Right [Line Items]
Number of shares sold							37,694
Shares issued, price per share | $ / shares							$ 1.75
Private Placement Warrants | Common Stock | February 2024 Private Placement
Class of Warrant or Right [Line Items]
Number of shares sold			274,182
Shares issued, price per share | $ / shares			$ 10.15
Common Warrants | February 2024 Private Placement
Class of Warrant or Right [Line Items]
Exercise price of warrants | $ / shares			$ 14
Common Warrants | Common Stock | February 2024 Private Placement
Class of Warrant or Right [Line Items]
Warrants issued			274,182
Common Warrants | Common Stock | Private Placement
Class of Warrant or Right [Line Items]
Warrants issued		193,000
Common and Pre-Funded Warrants | February 2024 Private Placement
Class of Warrant or Right [Line Items]
Warrants issued			90,363
Shares issued, price per share | $ / shares			$ 10.1486
ADDF Warrant
Class of Warrant or Right [Line Items]
Proceeds from issuance of common stock | $								$ 570,000
Number of trading days | TradingDay	30
Warrant expiration date	Mar. 29, 2029							Mar. 29, 2029
ADDF Warrant | Securities Purchase Agreement
Class of Warrant or Right [Line Items]
Exercise price of warrants | $ / shares	$ 7.64
ADDF Warrant | Common Stock
Class of Warrant or Right [Line Items]
Number of shares sold								229,057

Common Stock Reserved For Iss_3

Common Stock Reserved For Issuance - Common Stock Reserved For Potential Future Issuances (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Total shares of common stock reserved	2,165,820	881,116
Shares Underlying Outstanding Stock Options
Class Of Stock [Line Items]
Total shares of common stock reserved	19,111	14,323
Shares Available For Future Stock Option Grants
Class Of Stock [Line Items]
Total shares of common stock reserved	18,570	528
Shares Underlying Outstanding Public Warrants
Class Of Stock [Line Items]
Total shares of common stock reserved	685,714	685,714
Shares Underlying Outstanding Private Placement Warrants
Class Of Stock [Line Items]
Total shares of common stock reserved	983,981	37,694
Shares Underlying Convertible Preferred Stock-if Converted
Class Of Stock [Line Items]
Total shares of common stock reserved	225,225
Shares Underlying Outstanding Pre-funded Warrants
Class Of Stock [Line Items]
Total shares of common stock reserved	233,220	142,857

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)		3 Months Ended		12 Months Ended
	Jan. 01, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved		2,165,820		881,116
Weighted-average grant date fair value of stock options granted to employees and directors		$ 5.7	$ 60.9
Aggregate grant date fair value of stock options vested		$ 70,586	$ 121,585
Total unrecognized compensation cost related to stock options granted to employees		$ 337,032		$ 448,511
2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved		2,024
Percentage of total shares of common stock reserved		2%
Additional shares of common stock	17,849
2018 Omnibus Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of voting power of all classes of stock to be owned by optionee to determine the exercise price		10%
Exercise price as a percentage of fair value of common stock on grant date if optionee owns stock representing more than 10 percent of voting power of all classes of stock		110%
Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost related to stock options granted to employees, weighted-average recognition period		3 years 4 months 13 days		2 years 1 month 28 days
Employee Stock Options | 2011 Employee Equity Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year		10 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year		10 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Maximum | Board of Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of stock option grants		8 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Options, Balance	14,323
Stock Options, Granted	5,365
Stock Options, Forfeited	(565)
Stock Options, Expired	(12)
Stock Options, Balance	19,111	14,323
Stock Options, Exercisable	7,055
Weighted-Average Exercise Price, Balance	$ 446.93
Weighted-Average Exercise Price, Granted	8.21
Weighted-Average Exercise Price, Forfeited	626.18
Weighted-Average Exercise Price, Expired	3,129
Weighted-Average Exercise Price, Balance	316.90	$ 446.93
Weighted-Average Exercise Price, Exercisable	$ 712.15
Weighted-Average Remaining Contractual Life (Years), Balance	8 years 2 months 12 days	7 years 8 months 12 days
Weighted-Average Remaining Contractual Life (Years), Granted	10 years
Weighted-Average Remaining Contractual Life (Years), Exercisable	6 years 3 months 18 days

Stock-Based Compensation - Gran

Stock-Based Compensation - Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions (Details) - Employee Stock Options	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years	6 years
Expected volatility	75%	75%
Risk-free interest rate	4.20%	3.90%

Stock-Based Compensation - Tota

Stock-Based Compensation - Total Stock-Based Compensation Expense Recognized in Condensed Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 96	$ 129
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	42	51
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 54	$ 78

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0
Unrecognized tax benefits that would impact effective tax rate	$ 0		$ 0

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share as They Had Anti-Dilutive Effect (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Public Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	685,714
If Converted Common Shares From Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	9,900
Private Placement Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	275,584
Employee Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	14,722	8,196

Segment and Geographic Informat

Segment and Geographic Information - Additional Information (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2024 BusinessActivity Segment SegmentManager	Dec. 31, 2023 Segment
Segment Reporting Information [Line Items]
Number of business activity | BusinessActivity	1
Number of segment managers held accountable for operations or operating results | SegmentManager	0
United States
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	1	1

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)					3 Months Ended
	Mar. 27, 2024	Oct. 03, 2023	May 15, 2023	Mar. 30, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Lease expense incurred under operating lease					$ 45,144	$ 45,144
Sale of stock, transaction date				Mar. 27, 2024
Common stock, shares issued					1,584,305		892,622
Public Warrants
Related Party Transaction [Line Items]
Sale of stock, transaction date		Oct. 03, 2023
March 2023 Private Placement
Related Party Transaction [Line Items]
Sale of stock, transaction date				Mar. 30, 2023
March 2023 Private Placement | FCMI Parent Co.
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock				$ 2,000,000
Common stock, shares issued				23,229
March 2023 Private Placement | Vaccinex (Rochester) L.L.C.
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock				$ 2,000,000
Common stock, shares issued				23,229
Public Offering and Private Placement
Related Party Transaction [Line Items]
Aggregate purchase price	$ 1,250,000
Shares issued, price per share	$ 7.77
Common Stock
Related Party Transaction [Line Items]
Aggregate number of shares issued and sell	159,683
Common Stock | Public Warrants
Related Party Transaction [Line Items]
Aggregate number of shares issued and sell	193,000	542,857
Warrants issued		542,857
Shares issued, price per share		$ 14
Common Stock | Private Placement
Related Party Transaction [Line Items]
Warrants issued	159,683
Common Stock | Private Placement | Common Warrants
Related Party Transaction [Line Items]
Warrants issued	193,000
Common Stock | March 2023 Private Placement
Related Party Transaction [Line Items]
Aggregate number of shares issued and sell				23,693
Shares issued, price per share				$ 86.1
Gross proceeds from issuance of common stock				$ 2,040,000
Common Stock | May 2023 Private Placement
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock			$ 2,960,000
Common Stock | Public Offering and Private Placement
Related Party Transaction [Line Items]
Aggregate purchase price	$ 1,500,000
Shares issued, price per share	$ 7.77