v3.26.1
Segments - Summary of the Segment Profit or Loss, Including Significant Segment Expenses (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Segment expenses $ 219,585 $ 32,486
Net loss (219,585) (32,486)
Telitacicept - gMG    
Segment Reporting Information [Line Items]    
Segment expenses 9,793  
Telitacicept - SjD    
Segment Reporting Information [Line Items]    
Segment expenses 2,500  
Trem-cel    
Segment Reporting Information [Line Items]    
Segment expenses 250 6,382
VCAR33    
Segment Reporting Information [Line Items]    
Segment expenses 73 3,636
Other Research and Development    
Segment Reporting Information [Line Items]    
Segment expenses 776 2,995
Salaries and Benefits    
Segment Reporting Information [Line Items]    
Segment expenses 7,555 11,613
General Corporate Activities    
Segment Reporting Information [Line Items]    
Segment expenses 4,974 5,169
Other Segment Items    
Segment Reporting Information [Line Items]    
Segment expenses $ 193,664 $ 2,691