v3.26.1
Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Cash flows from operating activities:    
Net (loss) income $ (57.6) $ 82.9
Adjustments to reconcile net (loss) income to net cash used in operating activities:    
Depreciation and amortization 0.7 0.7
Net accretion of bond discounts/premiums (1.7) (3.8)
Amortization of right-of-use assets 0.4 0.6
Amortization of collaboration contract asset 0.3 3.3
Stock-based compensation 12.1 15.0
Changes in operating assets and liabilities:    
Accounts receivable (0.8) 5.3
Other receivables 0.8 0.0
Prepaid expenses and other assets (0.6) (2.7)
Accounts payable and accrued liabilities (6.8) (0.8)
Operating lease liability (0.4) (0.5)
Deferred revenue (15.6) (188.9)
Net cash used in operating activities (69.2) (88.9)
Cash flows from investing activities:    
Purchases of marketable securities (178.9) (119.6)
Maturities of marketable securities 165.0 189.5
Sales of marketable securities 28.9 0.0
Purchases of property, equipment and leasehold improvements (1.3) (0.4)
Net cash provided by investing activities 13.7 69.5
Cash flows from financing activities:    
Repayments of long-term debt (0.1) (0.1)
Net cash used in financing activities (0.1) (0.1)
Net decrease in cash and cash equivalents (55.6) (19.5)
Cash and cash equivalents, beginning of the period 142.9 100.5
Cash and cash equivalents, end of the period 87.3 81.0
Supplemental disclosure of cash flow information:    
Purchases of property, equipment and leasehold improvements unpaid at period end $ 0.0 $ 0.1