v3.26.1
Document and Entity Information
Jul. 13, 2026
Cover [Abstract]  
Entity Registrant Name AGENUS INC
Amendment Flag false
Entity Central Index Key 0001098972
Document Type 8-K
Document Period End Date Jul. 13, 2026
Entity Incorporation State Country Code DE
Entity File Number 000-29089
Entity Tax Identification Number 06-1562417
Entity Address, Address Line One 3 Forbes Road
Entity Address, City or Town Lexington
Entity Address, State or Province MA
Entity Address, Postal Zip Code 02421
City Area Code (781)
Local Phone Number 674-4400
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Common Stock, $0.01 par value per share
Trading Symbol AGEN
Security Exchange Name NASDAQ
Entity Emerging Growth Company false