v3.25.2
Cover
Aug. 12, 2025
Cover [Abstract]  
Document Type 8-K
Document Period End Date Aug. 12, 2025
Entity Registrant Name SELLAS Life Sciences Group, Inc.
Entity Incorporation, State or Country Code DE
Entity File Number 001-33958
Entity Tax Identification Number 20-8099512
Entity Address, Address Line One 7 Times Square, Suite 2503
Entity Address, City or Town New York
Entity Address, State or Province NY
Entity Address, Postal Zip Code 10036
City Area Code (646)
Local Phone Number 200-5278
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, $0.0001 par value per share
Trading Symbol SLS
Security Exchange Name NASDAQ
Entity Emerging Growth Company false
Entity Central Index Key 0001390478
Amendment Flag false