v3.26.3
Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Cash flows from operating activities:      
Net loss $ (121,636) $ (198,806)  
Adjustments to reconcile net loss to net cash used in operating activities:      
Share-based compensation expense 18,752 27,811  
Depreciation and amortization 3,269 5,086  
Deferred income tax provision (benefit) 792 (1,693)  
Changes in operating assets and liabilities:      
Research and development incentives receivable (17,394) (28,395)  
Prepaid expenses and other assets 3,228 (9,946)  
Operating lease right-of-use assets 2,296 3,407  
Accounts payable (216) (3,990)  
Accrued expenses and other current liabilities (7,678) 2,093  
Operating lease liabilities (2,526) (4,046)  
Deferred revenue (34,720) (21,850)  
Net cash used in operating activities (155,833) (230,329)  
Cash flows from investing activities:      
Purchases of property and equipment (1,283) (1,776)  
Net cash used in investing activities (1,283) (1,776)  
Cash flows from financing activities:      
Proceeds from the exercise of share options and settlement of restricted share units 16 4  
Payments of finance lease obligations (151) (120)  
Net cash used in financing activities (135) (116)  
Effect of exchange rate changes on cash, cash equivalents and restricted cash (1,479) 1,026  
Net decrease in cash, cash equivalents and restricted cash (158,730) (231,195)  
Cash, cash equivalents and restricted cash at beginning of period 628,715 880,067 $ 880,067
Cash, cash equivalents and restricted cash at end of period 469,985 648,872 628,715
Reconciliation of cash, cash equivalents and restricted cash      
Cash and cash equivalents $ 469,928 $ 648,325 628,110
Restricted Cash and Cash Equivalent, Statement of Financial Position [Extensible Enumeration] Other Assets, Noncurrent, Prepaid Expense and Other Assets, Current Other Assets, Noncurrent, Prepaid Expense and Other Assets, Current  
Restricted cash in prepaid expenses and other current assets   $ 547  
Restricted cash in other assets $ 57    
Total cash, cash equivalents and restricted cash 469,985 648,872 $ 628,715
Supplemental disclosure of cash flow information      
Cash paid for interest on finance lease obligations 55 58  
Cash paid for (received from) income taxes 147 (888)  
Cash paid for amounts included in the measurement of operating lease liabilities 3,222 4,461  
Changes in purchases of property and equipment in accounts payable and accrued expenses $ 227 $ 63