v3.25.1
Cover
Jun. 03, 2025
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Jun. 03, 2025
Entity File Number 001-33958
Entity Registrant Name SELLAS Life Sciences Group, Inc.
Entity Central Index Key 0001390478
Entity Tax Identification Number 20-8099512
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 7 Times Square
Entity Address, Address Line Two 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