Description of Business	12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]
Description of Business	Note 1. Description of Business (As Restated) Eledon Pharmaceuticals, Inc. is a clinical stage biotechnology company using its immunology expertise in targeting the CD40 Ligand (“CD40L”) pathway to develop therapies to protect transplanted organs and prevent rejection, and to treat amyotrophic lateral sclerosis (“ALS”). The Company’s lead compound in development is tegoprubart, an IgG1, anti-CD40L antibody with high affinity for the CD40 Ligand, a well-validated biological target that we believe has broad therapeutic potential. Unless otherwise indicated, references to the terms “Eledon,” “our,” “us,” “we,” or the “Company” refer to Eledon Pharmaceuticals, Inc. and its wholly owned subsidiaries, on a consolidated basis. On September 14, 2020, Eledon acquired Anelixis Therapeutics, Inc. (“Anelixis”), a privately held clinical stage biotechnology company developing a next generation anti-CD40L antibody as a potential treatment for organ and cellular transplantation, autoimmune diseases, and neurodegenerative diseases. The Company maintains its corporate headquarters in Irvine, California and has research and development facilities in Burlington, Massachusetts. Restatement of Previously Issued Consolidated Financial Statements In the course of preparing the Company’s Condensed Consolidated Financial Statements as of and for the three and six months ended June 30, 2025, the Company reassessed the rights and preferences of its Series X and Series X1 non-voting convertible preferred stock, $0.001 par value (“Preferred Stock”), and concluded that, because they are substantially identical to those of its common stock, $0.001 par value, the Preferred Stock should be treated as a separate class of common stock for purposes of calculating earnings per share in accordance with Accounting Standards Codification (“ASC”) 260-10, “Earnings Per Share.” As a result, the Company determined that it should have presented earnings per share under the two-class method in prior reporting periods. Additionally, in connection with this reassessment, the Company concluded that it had incorrectly classified the Preferred Stock as permanent equity in the consolidated balance sheets. The Preferred Stock includes a provision that, upon the occurrence of a fundamental transaction (which includes a third-party tender or exchange offer) in which more than 50 percent of the common stockholders receive cash or other assets, the holders of Preferred Stock, upon any subsequent conversion, are entitled to receive the same form of consideration, even if they did not participate in the original transaction. Because this feature may result in settlement in cash or other non-equity consideration upon an event outside the Company’s control, the Preferred Stock does not meet the criteria for permanent equity classification and is instead classified as temporary equity under ASC 480-10-S99-3A. Although a tender offer is not considered probable as of the current reporting date and redemption is not deemed probable, the existence of this provision requires classification as temporary equity. The Preferred Stock is not subsequently remeasured to its redemption value because redemption is not considered probable. Certain consolidated financial statements and financial information are presented herein as restated. See Note 12 Restatement of Previously Issued Consolidated Financial Statements for further information.

Description of Business

12 Months Ended

Dec. 31, 2024

Note 1. Description of Business (As Restated)

Eledon Pharmaceuticals, Inc. is a clinical stage biotechnology company using its immunology expertise in targeting the CD40 Ligand (“CD40L”) pathway to develop therapies to protect transplanted organs and prevent rejection, and to treat amyotrophic lateral sclerosis (“ALS”). The Company’s lead compound in development is tegoprubart, an IgG1, anti-CD40L antibody with high affinity for the CD40 Ligand, a well-validated biological target that we believe has broad therapeutic potential. Unless otherwise indicated, references to the terms “Eledon,” “our,” “us,” “we,” or the “Company” refer to Eledon Pharmaceuticals, Inc. and its wholly owned subsidiaries, on a consolidated basis.

On September 14, 2020, Eledon acquired Anelixis Therapeutics, Inc. (“Anelixis”), a privately held clinical stage biotechnology company developing a next generation anti-CD40L antibody as a potential treatment for organ and cellular transplantation, autoimmune diseases, and neurodegenerative diseases. The Company maintains its corporate headquarters in Irvine, California and has research and development facilities in Burlington, Massachusetts.

Restatement of Previously Issued Consolidated Financial Statements

In the course of preparing the Company’s Condensed Consolidated Financial Statements as of and for the three and six months ended June 30, 2025, the Company reassessed the rights and preferences of its Series X and Series X1 non-voting convertible preferred stock, $0.001 par value (“Preferred Stock”), and concluded that, because they are substantially identical to those of its common stock, $0.001 par value, the Preferred Stock should be treated as a separate class of common stock for purposes of calculating earnings per share in accordance with Accounting Standards Codification (“ASC”) 260-10, “Earnings Per Share.” As a result, the Company determined that it should have presented earnings per share under the two-class method in prior reporting periods.

Additionally, in connection with this reassessment, the Company concluded that it had incorrectly classified the Preferred Stock as permanent equity in the consolidated balance sheets. The Preferred Stock includes a provision that, upon the occurrence of a fundamental transaction (which includes a third-party tender or exchange offer) in which more than 50 percent of the common stockholders receive cash or other assets, the holders of Preferred Stock, upon any subsequent conversion, are entitled to receive the same form of consideration, even if they did not participate in the original transaction. Because this feature may result in settlement in cash or other non-equity consideration upon an event outside the Company’s control, the Preferred Stock does not meet the criteria for permanent equity classification and is instead classified as temporary equity under ASC 480-10-S99-3A. Although a tender offer is not considered probable as of the current reporting date and redemption is not deemed probable, the existence of this provision requires classification as temporary equity. The Preferred Stock is not subsequently remeasured to its redemption value because redemption is not considered probable.

Certain consolidated financial statements and financial information are presented herein as restated. See Note 12 Restatement of Previously Issued Consolidated Financial Statements for further information.