Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Feb. 28, 2022
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2021    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --12-31    
Entity Registrant Name Dyne Therapeutics, Inc.    
Entity Central Index Key 0001818794    
Entity File Number 001-39509    
Entity Incorporation, State or Country Code DE    
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    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
Entity Common Stock, Shares Outstanding   51,637,101  
Entity Shell Company false    
Document Annual Report true    
Document Transition Report false    
Title of 12(b) Security Common Stock, $0.0001 par value per share    
Trading Symbol DYN    
Security Exchange Name NASDAQ    
Entity Well Known Seasoned Issuer No    
Entity Voluntary Filers No    
ICFR Auditor Attestation Flag false    
Entity Public Float     $ 629.3
Documents Incorporated by Reference

The Registrant intends to file a definitive proxy statement pursuant to Regulation 14A relating to the 2022 Annual Meeting of Stockholders within 120 days of the end of the Registrant’s fiscal year ended December 31, 2021. Portions of such definitive proxy statement are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.

    
Auditor Firm ID 34    
Auditor Name Deloitte & Touche LLP    
Auditor Location Boston, Massachusetts