v3.24.0.1
Document and Entity Information Document
Nov. 20, 2023
Cover [Abstract]  
Document Type 8-K
Document Period End Date Jan. 28, 2024
Entity Registrant Name 2seventy bio, Inc.
Entity Incorporation, State or Country Code DE
Entity File Number 001-40791
Entity Tax Identification Number 86-3658454
Entity Address, Address Line One 60 Binney Street,
Entity Address, City or Town Cambridge
Entity Address, State or Province MA
Entity Address, Postal Zip Code 02142
City Area Code 339
Local Phone Number 499-9300
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, par value $0.0001 per share
Trading Symbol TSVT
Security Exchange Name NASDAQ
Entity Emerging Growth Company true
Entity Ex Transition Period false
Entity Central Index Key 0001860782
Amendment Flag false