v3.25.2
Cover Page - shares
 6 Months Ended
Jun. 30, 2025
Aug. 01, 2025
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2025  
Current Fiscal Year End Date --12-31  
Entity Registrant Name Q32 Bio Inc.  
Entity Central Index Key 0001661998  
Entity File Number 001-38433  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 47-3468154  
Entity Address, Address Line One 830 Winter Street  
Entity Address, City or Town Waltham  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02451  
Entity Interactive Data Current Yes  
Entity Current Reporting Status Yes  
City Area Code 781  
Local Phone Number 999-0232  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Title of 12(b) Security Common stock, par value $0.0001 per share  
Trading Symbol QTTB  
Security Exchange Name NASDAQ  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   12,197,615