| Document and Entity Information | Feb. 18, 2022 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 18, 2022 |
| Entity File Number | 001-39746 |
| Entity Registrant Name | SIGILON THERAPEUTICS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 47-4005543 |
| Entity Address, Address Line One | 100 Binney Street |
| Entity Address, Adress Line Two | Suite 600 |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02142 |
| City Area Code | 617 |
| Local Phone Number | 336-7540 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value per share |
| Trading Symbol | SGTX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001821323 |
| Amendment Flag | false |
