v3.26.1
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2026
Aug. 04, 2026
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Registrant Name Bolt Biotherapeutics, Inc.  
Entity Central Index Key 0001641281  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   1,926,345
Entity Shell Company false  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Title of 12(b) Security Common Stock, $0.00001 par value  
Trading Symbol BOLT  
Security Exchange Name NASDAQ  
Entity File Number 001-39988  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 47-2804636  
Entity Address, Address Line One 900 Chesapeake Drive  
Entity Address, City or Town Redwood City  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 94063  
City Area Code 650  
Local Phone Number 665-9295  
Document Quarterly Report true  
Document Transition Report false