v3.26.1
Segment Reporting - Summary of Segment Loss Including Significant Segment Expenses (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Research and development expenses:            
Interest expense and other expense, net $ (18)   $ (21)   $ (39) $ (49)
Net loss (38,319) $ (39,728) (42,081) $ (44,635) (78,047) (86,716)
Operating Segment            
Research and development expenses:            
Other research and development expenses [1] 13,378   12,289   28,015 27,090
General and administrative expenses [2] 14,768   8,594   26,062 18,569
Interest (income) (1,929)   (2,364)   (4,256) (5,189)
Interest expense and other expense, net 692   35   1,380 87
Net loss 38,319   42,081   78,047 86,716
Operating Segment | Miv-cel            
Research and development expenses:            
External research and development expenses allocated by program 11,386   22,541   26,616 44,661
Operating Segment | Other Programs            
Research and development expenses:            
External research and development expenses allocated by program $ 24   $ 986   $ 230 $ 1,498
[1] Primarily includes personnel costs, license fees, R&D consulting services, unallocated CRO and CMO costs and allocated overhead and facilities expenses.
[2] Primarily includes personnel costs, allocated overhead and facilities expenses, legal, IT, accounting and general and administrative expenses