Description of the Business	3 Months Ended
Description of the Business	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business Alto Neuroscience, Inc. (the “Company” or “Alto”) was incorporated in Delaware on March 25, 2019. The Company maintains its headquarters in Mountain View, California. The Company has one wholly-owned subsidiary in Australia that was formed during 2020 to conduct clinical trials. Alto is a clinical-stage biopharmaceutical company with a mission to redefine psychiatry by leveraging neurobiology to develop personalized and highly effective treatment options. Through insights derived from the Company’s scalable and proprietary Precision Psychiatry Platform, the Company aims to discover brain-based biomarkers to better identify which patients are more likely to respond to its novel product candidates. The Company’s current pipeline consists of seven clinical-stage assets addressing high-need therapeutic areas, including major depressive disorder (“MDD”), bipolar depression (“BPD”), treatment resistant depression (“TRD”), schizophrenia, and Parkinson’s disease. Liquidity and Capital Resources The Company has incurred significant operating losses since inception and has relied primarily upon equity financings to fund its operations. At March 31, 2026, the Company had an accumulated deficit of approximately $227.9 million. As the Company continues to incur losses, its transition to profitability will depend on the successful development, approval and commercialization of product candidates and on the generation of sufficient revenues to support its cost structure. No assurance can be provided that the Company will ever be profitable, and unless or until it becomes profitable, the Company will need to continue to raise additional capital. In February 2024, the Company completed its initial public offering (“IPO”) of its common stock. The Company issued and sold 9,246,000 shares of common stock at a public offering price of $16.00 per share, which included 1,206,000 shares sold pursuant to the exercise of the underwriters’ option to purchase additional shares, and received net proceeds of $133.0 million after deducting underwriting discounts and commissions and other offering costs. Upon completion of the IPO, all outstanding shares of the Company’s outstanding preferred stock converted into an aggregate of 13,664,261 shares of common stock. In addition, the IPO resulted in the net exercise and conversion of all outstanding Series A Preferred Stock Warrants for an aggregate of 72,631 shares of common stock. On October 21, 2025, the Company completed a private placement transaction in which it issued and sold (i) 3,832,263 shares of common stock and (ii) pre-funded warrants (in lieu of common stock) to purchase an aggregate of 4,622,251 shares of common stock. The Company received net proceeds of $49.7 million (see Note 10 for additional information). On November 17, 2025, K2 HealthVentures LLC elected to convert $4.0 million of its outstanding loan balance into the Company’s common stock. Pursuant to the terms of the Amended Loan Agreement, the conversion price was $4.83 per share, resulting in the issuance of 828,860 shares. On March 17, 2026, the Company completed a private placement transaction in which it issued and sold (i) 2,900,000 shares of common stock and (ii) pre-funded warrants (in lieu of common stock) to purchase an aggregate of 3,100,000 shares of common stock. The Company received net proceeds of $114.9 million (See Note 10 for additional information). On March 18, 2026, K2 HealthVentures LLC elected to convert $1.0 million of its outstanding loan balance into the Company’s common stock. Pursuant to the terms of the Amended Loan Agreement, the conversion price was $4.83 per share, resulting in the issuance of 207,215 shares.