v3.25.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2025
Aug. 13, 2025
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Entity Registrant Name Galera Therapeutics, Inc.  
Entity Central Index Key 0001563577  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Title of 12(b) Security Common Stock,$0.001 par value per share  
Trading Symbol GRTX  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   75,462,390
Entity File Number 001-39114  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 46-1454898  
Entity Address, Address Line One 101 Lindenwood Drive, Suite 225  
Entity Address, City or Town Malvern  
Entity Address, State or Province PA  
Entity Address, Postal Zip Code 19355  
City Area Code 610  
Local Phone Number 725-1500  
Document Quarterly Report true  
Document Transition Report false