Description of Business	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Allogene Therapeutics, Inc. (the Company or Allogene) was incorporated on November 30, 2017 in the State of Delaware and is headquartered in South San Francisco, California. Allogene is a clinical stage immuno-oncology company pioneering the development of genetically engineered allogeneic T cell product candidates for the treatment of cancer and autoimmune diseases. The Company is developing a pipeline of off-the-shelf T cell product candidates that are designed to target and kill cancer cells in patients or eliminate pathogenic autoreactive cells in patients with autoimmune disorders. The Company’s engineered T cells are allogeneic, meaning they are derived from healthy donors for intended use in any patient, rather than from an individual patient for that patient’s use, as in the case of autologous T cells. The Company believes this key difference will enable it to deliver readily available treatments faster, more reliably, at greater scale, and to more patients. Public Offerings In November 2019, the Company entered into a sales agreement with TD Securities (USA) LLC (f/k/a Cowen and Company, LLC) (TD Cowen), as amended on November 2, 2022 and November 2, 2023, under which the Company may from time to time issue and sell shares of its common stock through TD Cowen in at-the-market (ATM) offerings. The aggregate compensation payable to TD Cowen as the Company’s sales agent equals up to 3.0% of the gross sales price of the shares sold through TD Cowen pursuant to the sales agreement. The specified dollar limit on the amount of common stock that may be sold under the sales agreement was removed pursuant to the November 2, 2023 amendment to the sales agreement. During the three months ended March 31, 2026, the Company sold an aggregate of 12,476,533 shares of common stock in ATM offerings resulting in net proceeds of $20.7 million. On April 13, 2026, in connection with the Company’s April 2026 Public Offering as described in Notes 9 and 13, the Company suspended any further ATM offering under the TD Cowen sales agreement until a new prospectus or prospectus supplement is filed with the Securities and Exchange Commission (SEC). Need for Additional Capital The Company has sustained operating losses and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities as well as the ability to commercialize the Company’s product candidates. The Company had cash, cash equivalents and investments of $266.9 million as of March 31, 2026. Since inception through March 31, 2026, the Company has incurred cumulative net losses of $2,053.3 million. Management expects to incur additional losses in the future to fund its operations and conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan. The Company may raise additional capital through the issuance of equity securities, debt financings, collaborations or other sources to further implement its business plan. If additional financing is not available at adequate levels, the Company may need to reevaluate its operating plan and may be required to delay the development of its product candidates. The Company expects that its cash, cash equivalents and investments as of March 31, 2026, together with the net proceeds from the April 2026 Public Offering as described in Notes 9 and 13, will be sufficient to fund its operations for at least the next 12 months from the date the accompanying unaudited condensed financial statements are filed with the SEC.

Allogene Therapeutics, Inc. (the Company or Allogene) was incorporated on November 30, 2017 in the State of Delaware and is headquartered in South San Francisco, California. Allogene is a clinical stage immuno-oncology company pioneering the development of genetically engineered allogeneic T cell product candidates for the treatment of cancer and autoimmune diseases. The Company is developing a pipeline of off-the-shelf T cell product candidates that are designed to target and kill cancer cells in patients or eliminate pathogenic autoreactive cells in patients with autoimmune disorders. The Company’s engineered T cells are allogeneic, meaning they are derived from healthy donors for intended use in any patient, rather than from an individual patient for that patient’s use, as in the case of autologous T cells. The Company believes this key difference will enable it to deliver readily available treatments faster, more reliably, at greater scale, and to more patients.

In November 2019, the Company entered into a sales agreement with TD Securities (USA) LLC (f/k/a Cowen and Company, LLC) (TD Cowen), as amended on November 2, 2022 and November 2, 2023, under which the Company may from time to time issue and sell shares of its common stock through TD Cowen in at-the-market (ATM) offerings. The aggregate compensation payable to TD Cowen as the Company’s sales agent equals up to 3.0% of the gross sales price of the shares sold through TD Cowen pursuant to the sales agreement. The specified dollar limit on the amount of common stock that may be sold under the sales agreement was removed pursuant to the November 2, 2023 amendment to the sales agreement. During the three months ended March 31, 2026, the Company sold an aggregate of 12,476,533 shares of common stock in ATM offerings resulting in net proceeds of $20.7 million. On April 13, 2026, in connection with the Company’s April 2026 Public Offering as described in Notes 9 and 13, the Company suspended any further ATM offering under the TD Cowen sales agreement until a new prospectus or prospectus supplement is filed with the Securities and Exchange Commission (SEC).

The Company has sustained operating losses and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities as well as the ability to commercialize the Company’s product candidates.

The Company had cash, cash equivalents and investments of $266.9 million as of March 31, 2026. Since inception through March 31, 2026, the Company has incurred cumulative net losses of $2,053.3 million. Management expects to incur additional losses in the future to fund its operations and conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan.