| Document and Entity Information | Jan. 26, 2024 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 26, 2024 |
| Entity Registrant Name | EVELO BIOSCIENCES, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38473 |
| Entity Tax Identification Number | 46-5594527 |
| Entity Address Address Line 1 | 124 Washington Street |
| Entity Address Address Line 2 | Suite 101 |
| Entity Address City Or Town | Foxboro |
| Entity Address State Or Province | MA |
| Entity Address Postal Zip Code | 02035 |
| City Area Code | 617 |
| Local Phone Number | 577-0300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001694665 |
| Amendment Flag | false |
| Former Address [Member] | |
| Document And Entity Information [Line Items] | |
| Entity Address Address Line 1 | One Kendall Square |
| Entity Address Address Line 2 | 600/700 |
| Entity Address Address Line 3 | Suite 7-201 |
| Entity Address City Or Town | Cambridge |
| Entity Address State Or Province | MA |
| Entity Address Postal Zip Code | 02139 |
