| Document and Entity Information | Mar. 30, 2023 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001107421 |
| Document Type | 8-K |
| Document Period End Date | Mar. 30, 2023 |
| Entity Registrant Name | Alaunos Therapeutics, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-33038 |
| Entity Tax Identification Number | 84-1475642 |
| Entity Address, Address Line One | 8030 El Rio Street |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77054 |
| City Area Code | (346) |
| Local Phone Number | 355-4099 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.001 per share |
| Trading Symbol | TCRT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
