Nature of the Business and Basis of Presentation	3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Vigil Neuroscience, Inc., together with its consolidated subsidiary, Vigil Neuroscience Security Corporation (“Vigil” or the “Company”), is a clinical-stage biotechnology company dedicated to improving the lives of patients, caregivers and families affected by rare and common neurodegenerative diseases by pursuing the development of disease-modifying therapeutics to restore the vigilance of microglia. Microglia are the sentinel immune cells of the brain and play a critical role in maintaining central nervous system (CNS) health and responding to damage caused by disease. Leveraging recent research implicating microglial dysfunction in neurodegenerative diseases, the Company utilizes a precision medicine approach to develop a pipeline of therapeutic candidates, initially addressing genetically defined patient subpopulations, that it believes will activate and restore microglial function. The Company was incorporated in the State of Delaware in June 2020 and is located in Watertown, Massachusetts. The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, completing preclinical studies and clinical trials, the ability to raise additional capital to fund operations, obtaining regulatory approval for therapeutic candidates, market acceptance of products, competition from substitute products, protection of proprietary intellectual property, compliance with government regulations, dependence on key personnel, reliance on third-party organizations and the clinical and commercial success of its therapeutic candidates. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Going Concern The Company has evaluated whether there are certain conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the condensed consolidated financial statements are issued. As of March 31, 2025, the Company had cash, cash equivalents, and marketable securities of $87.1 million. The Company has incurred recurring losses since its inception, and as of March 31, 2025, the Company had an accumulated deficit of $329.4 million. On March 21, 2023, the Company entered into an Open Market Sales Agreement, or the ATM facility, with Jefferies LLC, or the Agent, pursuant to which the Company can sell, from time to time, at its option, up to an aggregate of $100.0 million of shares of its common stock, through the Agent, as its sales agent. During the year ended December 31, 2024, the Company sold 2,887,021 shares of common stock under the ATM facility at an average price of $3.41 per share, for net proceeds after deducting commissions and other offering expenses of $9.5 million. During the three months ended March 31, 2025, the Company sold 5,784,772 shares of common stock under the ATM facility at an average price of $2.36 per share, for net proceeds after deducting commissions and other offering expenses of $13.3 million. On June 27, 2024, the Company entered into a Securities Purchase Agreement (SPA) with Aventis Inc., a wholly-owned subsidiary of Sanofi, a global healthcare and pharmaceutical company, (together with Aventis Inc., "Sanofi"). Pursuant to the SPA, on July 1, 2024 the Company issued an aggregate of 537,634 shares of Series A non-voting convertible preferred stock (Series A Preferred Stock) for net proceeds of $39.6 million. (see Note 7). Based on its recurring losses from operations incurred since inception, accumulated deficit, expectation of continuing operating losses for the foreseeable future, and the need to raise additional capital to finance its future operations, as of May 7, 2025, the issuance date of the condensed consolidated financial statements for the quarter ended March 31, 2025, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year from the date that these condensed consolidated financial statements are issued. The Company will seek additional funding through equity financings, government or private-party grants, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or rights of the Company’s stockholders. If the Company is unable to obtain sufficient capital, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. The accompanying condensed consolidated 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. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Basis of Presentation The accompanying condensed consolidated financial statements reflect the operations of the Company are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) applicable to interim periods and, in the opinion of management, include all normal and recurring adjustments that are necessary to state fairly the results of operations for the reported periods. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Our condensed consolidated financial statements have also been prepared on a basis substantially consistent with, and should be read in conjunction with, our audited consolidated financial statements for the year ended December 31, 2024, which were included in our Annual Report on Form 10-K that was filed with the Securities and Exchange Commission on March 13, 2025. The year-end condensed consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. The results of our operations for any interim period are not necessarily indicative of the results of our operations for any other interim period or for a full fiscal year. The accompanying condensed consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiary. Intercompany balances and transactions have been eliminated in consolidation.

Nature of the Business and Basis of Presentation

3 Months Ended

Mar. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Vigil Neuroscience, Inc., together with its consolidated subsidiary, Vigil Neuroscience Security Corporation (“Vigil” or the “Company”), is a clinical-stage biotechnology company dedicated to improving the lives of patients, caregivers and families affected by rare and common neurodegenerative diseases by pursuing the development of disease-modifying therapeutics to restore the vigilance of microglia. Microglia are the sentinel immune cells of the brain and play a critical role in maintaining central nervous system (CNS) health and responding to damage caused by disease. Leveraging recent research implicating microglial dysfunction in neurodegenerative diseases, the Company utilizes a precision medicine approach to develop a pipeline of therapeutic candidates, initially addressing genetically defined patient subpopulations, that it believes will activate and restore microglial function. The Company was incorporated in the State of Delaware in June 2020 and is located in Watertown, Massachusetts.

The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, completing preclinical studies and clinical trials, the ability to raise additional capital to fund operations, obtaining regulatory approval for therapeutic candidates, market acceptance of products, competition from substitute products, protection of proprietary intellectual property, compliance with government regulations, dependence on key personnel, reliance on third-party organizations and the clinical and commercial success of its therapeutic candidates. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Going Concern

The Company has evaluated whether there are certain conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the condensed consolidated financial statements are issued. As of March 31, 2025, the Company had cash, cash equivalents, and marketable securities of $87.1 million. The Company has incurred recurring losses since its inception, and as of March 31, 2025, the Company had an accumulated deficit of $329.4 million.

On March 21, 2023, the Company entered into an Open Market Sales Agreement, or the ATM facility, with Jefferies LLC, or the Agent, pursuant to which the Company can sell, from time to time, at its option, up to an aggregate of $100.0 million of shares of its common stock, through the Agent, as its sales agent. During the year ended December 31, 2024, the Company sold 2,887,021 shares of common stock under the ATM facility at an average price of $3.41 per share, for net proceeds after deducting commissions and other offering expenses of $9.5 million. During the three months ended March 31, 2025, the Company sold 5,784,772 shares of common stock under the ATM facility at an average price of $2.36 per share, for net proceeds after deducting commissions and other offering expenses of $13.3 million.

On June 27, 2024, the Company entered into a Securities Purchase Agreement (SPA) with Aventis Inc., a wholly-owned subsidiary of Sanofi, a global healthcare and pharmaceutical company, (together with Aventis Inc., "Sanofi"). Pursuant to the SPA, on July 1, 2024 the Company issued an aggregate of 537,634 shares of Series A non-voting convertible preferred stock (Series A Preferred Stock) for net proceeds of $39.6 million. (see Note 7).

Based on its recurring losses from operations incurred since inception, accumulated deficit, expectation of continuing operating losses for the foreseeable future, and the need to raise additional capital to finance its future operations, as of May 7, 2025, the issuance date of the condensed consolidated financial statements for the quarter ended March 31, 2025, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year from the date that these condensed consolidated financial statements are issued.

The Company will seek additional funding through equity financings, government or private-party grants, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or rights of the Company’s stockholders.

If the Company is unable to obtain sufficient capital, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

The accompanying condensed consolidated 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. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.

Basis of Presentation

The accompanying condensed consolidated financial statements reflect the operations of the Company are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) applicable to interim periods and, in the opinion of management, include all normal and recurring adjustments that are necessary to state fairly the results of operations for the reported periods. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Our condensed consolidated financial statements have also been prepared on a basis substantially consistent with, and should be read in conjunction with, our audited consolidated financial statements for the year ended December 31, 2024, which were included in our Annual Report on Form 10-K that was filed with the Securities and Exchange Commission on March 13, 2025. The year-end condensed consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. The results of our operations for any interim period are not necessarily indicative of the results of our operations for any other interim period or for a full fiscal year.

The accompanying condensed consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiary. Intercompany balances and transactions have been eliminated in consolidation.