| Document and Entity Information | Dec. 08, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001556263 |
| Document Type | 8-K |
| Document Period End Date | Dec. 8, 2020 |
| Entity Registrant Name | Syros Pharmaceuticals, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-37813 |
| Entity Tax Identification Number | 45-3772460 |
| Entity Address, Address Line One | 35 CambridgePark Drive |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02140 |
| City Area Code | (617) |
| Local Phone Number | 744-1340 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.001 par value |
| Trading Symbol | SYRS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
