v3.22.4
Document And Entity Information
Mar. 10, 2023
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Mar. 10, 2023
Entity Registrant Name IGM Biosciences, Inc.
Entity Central Index Key 0001496323
Entity Emerging Growth Company true
Securities Act File Number 001-39045
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 77-0349194
Entity Address, Address Line One 325 E. Middlefield Road
Entity Address, City or Town Mountain View
Entity Address, State or Province CA
Entity Address, Postal Zip Code 94043
City Area Code (650)
Local Phone Number 965-7873
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Ex Transition Period false
Title of 12(b) Security Common Stock, par value $0.01 per share
Trading Symbol IGMS
Security Exchange Name NASDAQ