Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net loss	$ (366,252)	$ (153,610)	$ (650,175)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	19,259	19,837	24,172
Stock-based compensation	86,567	81,028	97,947
Other non-cash items, net	(38,618)	(16,545)	12,470
Acquired in-process research and development	0	2,500	0
Changes in:
Accounts receivable	175,000	(200,000)	305
Prepaid expenses and other assets	5,285	23,219	1,598
Accounts payable and accrued expenses	(27,283)	(20,247)	5,164
Deferred revenue	(1,949)	5,794	(1,011)
Operating lease assets and liabilities	(4,407)	(2,461)	15,310
Other liabilities, net	9,624	110	(1,521)
Net cash used in operating activities	(142,774)	(260,375)	(495,741)
Investing activities
Purchase of property, plant and equipment	(1,901)	(9,470)	(37,188)
Purchase of in-process research and development	0	(2,500)	0
Investment in equity securities	(23,183)	0	0
Purchases of marketable debt securities	(1,463,196)	(1,065,911)	(1,417,800)
Maturities of marketable debt securities	1,207,799	1,452,528	1,196,333
Net cash (used in) provided by investing activities	(280,481)	374,647	(258,655)
Financing activities
Proceeds from issuance of common shares, net of issuance costs	300,695	32,721	970
Proceeds from exercise of options and ESPP contributions, net of issuance costs	31,289	29,943	37,622
Net cash provided by financing activities	331,984	62,664	38,592
Effect of exchange rate changes on cash	(21)	73	(80)
(Decrease) increase in cash	(91,292)	177,009	(715,884)
Cash, cash equivalents and restricted cash, beginning of period	401,068	224,060	939,944
Cash, cash equivalents and restricted cash, end of period	309,776	401,068	224,060
Supplemental disclosure of non-cash investing and financing activities
Property and equipment purchases in accounts payable and accrued expenses	154	725	2,121
Equity issuance costs in accounts payable and accrued expenses	$ 3,371	$ 417	$ 99