XML 7 R1.htm IDEA: XBRL DOCUMENT v3.25.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2025
May 06, 2025
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2025  
Document Fiscal Period Focus Q1  
Document Fiscal Year Focus 2025  
Entity Registrant Name AGENUS INC  
Entity Central Index Key 0001098972  
Entity Current Reporting Status Yes  
Trading Symbol AGEN  
Security Exchange Name NASDAQ  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Shell Company false  
Entity Small Business false  
Entity Emerging Growth Company false  
Title of 12(b) Security Common stock, par value $0.01  
Entity Interactive Data Current Yes  
Entity Common Stock, Shares Outstanding   27,416,850
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  
Document Quarterly Report true  
Document Transition Report false  
Entity Incorporation, State or Country Code DE