v3.25.2
License and Collaboration Agreements - Additional Information (Details) - USD ($)
 3 Months Ended 6 Months Ended
May 15, 2025
Jun. 11, 2021
Jun. 30, 2025
Jun. 30, 2024
Mar. 31, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Upfront payment received           $ 625,000,000    
License and collaboration revenue     $ 0 $ 35,000,000   0 $ 35,000,000  
Accrued clinical trial costs     36,462,000     36,462,000   $ 17,896,000
Increase (decrease) in commodity contract assets and liabilities           0    
GAL-301 clinical study                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
License and collaboration revenue       $ 35,000,000     $ 35,000,000  
GSK Collaboration Agreement                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Termination payment $ 32,000,000              
Remaining days for the payment no later than 20 business days after receipt of an invoice from GSK to close out the remaining costs for which it is responsible under the contract.              
Adimab L L C                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Maximum additional receivable based on achievement of research milestones           14,500,000    
Adimab L L C | License revenue                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Additional milestone payment accrued 1     1,000,000   $ 1,000,000 1,000,000    
Amount of development milestone               3,000,000
License agreement milestone payments paid           10,400,000    
Adimab L L C | Development Regulatory and Sales Milestone                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Maximum option fees receivable based on achievement of research milestones     45,800,000     45,800,000    
GSK                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
Upfront payment received   $ 625,000,000            
Milestone payments   $ 1,450,000,000            
Eligible royalty payments percentage   20.00%            
Accrued clinical trial costs     32,000,000     32,000,000    
Deferred revenue     0     0   $ 0
Costs related to the cost-sharing provisions     35,200,000     43,200,000    
GSK | License revenue                
Research And Development Arrangement Contract To Perform For Others [Line Items]                
License and collaboration revenue     $ 0     $ 0