Cover Page - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Mar. 23, 2026 |
Jun. 30, 2025 |
|
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Amendment Flag | true | ||
| Document Fiscal Year Focus | 2025 | ||
| Document Fiscal Period Focus | FY | ||
| Document Period End Date | Dec. 31, 2025 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Interactive Data Current | Yes | ||
| Document Annual Report | true | ||
| Document Transition Report | false | ||
| Entity Central Index Key | 0001829802 | ||
| Entity Registrant Name | Sensei Biotherapeutics, Inc. | ||
| Entity File Number | 001-39980 | ||
| Entity Tax Identification Number | 83-1863385 | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Current Reporting Status | Yes | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Shell Company | false | ||
| Entity Small Business | true | ||
| Entity Address, Address Line One | 1405 Research Boulevard | ||
| Entity Address, Address Line Two | Suite 125 | ||
| Entity Address, City or Town | Rockville | ||
| Entity Address, State or Province | MD | ||
| Entity Address, Postal Zip Code | 20850 | ||
| City Area Code | 240 | ||
| Local Phone Number | 243-8000 | ||
| Entity Emerging Growth Company | true | ||
| Trading Symbol | SNSE | ||
| Title of 12(b) Security | Common Stock, $0.0001 par value per share | ||
| Security Exchange Name | NASDAQ | ||
| Entity Common Stock, Shares Outstanding | 1,340,281 | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Public Float | $ 7.1 | ||
| ICFR Auditor Attestation Flag | false | ||
| Documents Incorporated by Reference [Text Block] | DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s definitive proxy statement, to be filed pursuant to Regulation 14A under the Securities Exchange Act of 1934, for its 2026 Annual Meeting of Stockholders are incorporated by reference in Part III of this Form
10-K. |
||
| Document Financial Statement Error Correction [Flag] | false | ||
| Entity Ex Transition Period | false | ||
| Amendment Description | Explanatory Note Sensei Biotherapeutics, Inc. (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (“Amendment No. 1”) to amend the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, which was originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 30, 2026 (the “Original Filing”). The purpose of this Amendment No. 1 is to amend and replace in its entirety Part I, Item 1. Business of the Original Filing in response to comments received from the staff of the SEC. In addition, pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, this Amendment No. 1 contains revised certifications pursuant to Section 302 of the Sarbanes-Oxley Act of 2002, which are attached hereto as Exhibits 31.3 and 31.4. Because no financial statements or other financial information have been included in this Amendment No. 1, paragraph 3 has been omitted from each of the revised Section 302 Certifications, and because this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 4 and 5 have been omitted from each of the revised Section 302 certifications. Except as described above, this Amendment No. 1 does not amend, modify, or otherwise update any other information in the Original Filing and does not reflect events occurring after the filing of the Original Filing. Accordingly, this Amendment No. 1 should be read in conjunction with the Original Filing and the Company’s other filings with the SEC. |