| Document and Entity Information | Mar. 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 10, 2022 |
| Entity Registrant Name | Dyne Therapeutics, Inc. |
| Entity Central Index Key | 0001818794 |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39509 |
| Entity Tax Identification Number | 36-4883909 |
| Entity Address, Address Line One | 1560 Trapelo Road |
| Entity Address, City or Town | Waltham |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02451 |
| City Area Code | 781 |
| Local Phone Number | 786-8230 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.0001 par value per share |
| Trading Symbol | DYN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
