Nature of Business	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	1. Nature of Business Syndax Pharmaceuticals, Inc. (“the Company” or “Syndax”) is a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. The Company's two lead product candidates are revumenib and axatilimab. The Company is developing revumenib, a potent, selective, small molecule inhibitor of the menin-MLL binding interaction for the treatment of KMT2A rearranged, (“KMT2Ar”), also known as mixed lineage leukemia rearranged, (“MLLr”), acute leukemias including acute lymphoblastic leukemia, (“ALL”), and acute myeloid leukemia, or AML, and nucleophosmin 1, also known as NPM1, mutant AML. The Company is also exploring the use of revumenib as a treatment in solid tumors, specifically its activity in metastatic colorectal cancer. The Company is developing axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1 receptor, (“CSF-1R”), in chronic graft-versus-host disease, (“cGVHD”), as well as idiopathic pulmonary fibrosis, (“IPF”). The Company plans to continue to leverage the technical and business expertise of its management team and scientific collaborators to license, acquire and develop additional therapeutics to expand its pipeline. Since its inception, the Company has devoted its efforts principally to research and development and raising capital. The Company is subject to risks common to companies in the development stage, including, but not limited to, successful development of therapeutics, obtaining additional funding, protection of proprietary therapeutics, compliance with government regulations, fluctuations in operating results, dependence on key personnel and collaborative partners, and risks associated with industry changes. The Company’s long-term success is dependent upon its ability to successfully develop and market its product candidates, expand its oncology drug pipeline, earn revenue, obtain additional capital when needed, and ultimately, achieve profitable operations. The Company anticipates that it will be several years before any of its product candidates is approved, if ever, and the Company begins to generate revenue from sales of such product candidates. Accordingly, management expects to incur substantial losses on the ongoing development of its product candidates and does not expect to achieve positive cash flow from operations for the foreseeable future, if ever. As a result, the Company will continue to require additional capital to move forward with its business plan. While certain amounts of this additional capital were raised in the past, there can be no assurance that funds necessary beyond these amounts will be available in amounts or on terms sufficient to ensure ongoing operations. The Company’s management believes that the cash, cash equivalents and short-term investments balances as of December 31, 2023, should enable the Company to maintain its planned operations for at least 12 months from the issuance date of these financial statements. The Company’s ability to fund all of its planned operations internally beyond that date, including the completion of its ongoing and planned clinical trial activities, may be substantially dependent upon whether the Company can obtain sufficient funding on terms acceptable to the Company. Proceeds from additional capital transactions would allow the Company to accelerate and/or expand its planned research and development activities. In the event that sufficient funds were not available, the Company may be required to delay or reduce expenditures to conserve cash, which could involve scaling back or curtailing development and selling, general and administrative activities. The Company is subject to challenges and risks specific to its business and ability to execute on the strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of the Company’s late-stage product candidate; delays or problems in the supply of the Company’s products, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing the Company’s intellectual property rights; complying with applicable regulatory requirements.

Nature of Business

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Nature of Business

Syndax Pharmaceuticals, Inc. (“the Company” or “Syndax”) is a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies. The Company's two lead product candidates are revumenib and axatilimab. The Company is developing revumenib, a potent, selective, small molecule inhibitor of the menin-MLL binding interaction for the treatment of KMT2A rearranged, (“KMT2Ar”), also known as mixed lineage leukemia rearranged, (“MLLr”), acute leukemias including acute lymphoblastic leukemia, (“ALL”), and acute myeloid leukemia, or AML, and nucleophosmin 1, also known as NPM1, mutant AML. The Company is also exploring the use of revumenib as a treatment in solid tumors, specifically its activity in metastatic colorectal cancer. The Company is developing axatilimab, a monoclonal antibody that blocks the colony stimulating factor 1 receptor, (“CSF-1R”), in chronic graft-versus-host disease, (“cGVHD”), as well as idiopathic pulmonary fibrosis, (“IPF”). The Company plans to continue to leverage the technical and business expertise of its management team and scientific collaborators to license, acquire and develop additional therapeutics to expand its pipeline.

Since its inception, the Company has devoted its efforts principally to research and development and raising capital. The Company is subject to risks common to companies in the development stage, including, but not limited to, successful development of therapeutics, obtaining additional funding, protection of proprietary therapeutics, compliance with government regulations, fluctuations in operating results, dependence on key personnel and collaborative partners, and risks associated with industry changes. The Company’s long-term success is dependent upon its ability to successfully develop and market its product candidates, expand its oncology drug pipeline, earn revenue, obtain additional capital when needed, and ultimately, achieve profitable operations. The Company anticipates that it will be several years before any of its product candidates is approved, if ever, and the Company begins to generate revenue from sales of such product candidates. Accordingly, management expects to incur substantial losses on the ongoing development of its product candidates and does not expect to achieve positive cash flow from operations for the foreseeable future, if ever. As a result, the Company will continue to require additional capital to move forward with its business plan. While certain amounts of this additional capital were raised in the past, there can be no assurance that funds necessary beyond these amounts will be available in amounts or on terms sufficient to ensure ongoing operations.

The Company’s management believes that the cash, cash equivalents and short-term investments balances as of December 31, 2023, should enable the Company to maintain its planned operations for at least 12 months from the issuance date of these financial statements. The Company’s ability to fund all of its planned operations internally beyond that date, including the completion of its ongoing and planned clinical trial activities, may be substantially dependent upon whether the Company can obtain sufficient funding on terms acceptable to the Company. Proceeds from additional capital transactions would allow the Company to accelerate and/or expand its planned research and development activities. In the event that sufficient funds were not available, the Company may be required to delay or reduce expenditures to conserve cash, which could involve scaling back or curtailing development and selling, general and administrative activities.

The Company is subject to challenges and risks specific to its business and ability to execute on the strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of the Company’s late-stage product candidate; delays or problems in the supply of the Company’s products, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing the Company’s intellectual property rights; complying with applicable regulatory requirements.