Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (95,020)	$ (60,462)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	999	712
Stock-based compensation expense	17,629	9,648
Amortization of operating lease right-of-use assets	2,092	1,630
Net accretion of discounts on investments	(10,991)	(5,990)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(4,958)	(4,702)
Other assets	(8,581)	615
Operating lease liabilities	(1,804)	(1,356)
Accounts payable	5,672	1,789
Accrued compensation	(7,968)	699
Accrued manufacturing expenses	(51,840)	6,689
Accrued expenses	(4,354)	3,038
Net cash used in operating activities	(159,124)	(47,690)
Cash flows from investing activities:
Purchases of property and equipment	(5,678)	(5,609)
Purchases of investments	(687,697)	(483,779)
Manufacturing facility and equipment construction-in-progress	(6,394)	0
Maturities of investments	242,318	40,160
Sale of investments	6,378	1,127
Net cash used in investing activities	(451,073)	(448,101)
Cash flows from financing activities:
Proceeds from exercise of common stock options	5,024	502
Proceeds from issuance of common stock related to at-the-market offering, net of issuance costs	0	41,787
Proceeds from issuance of common stock from follow-on offering, net of issuance costs	816,478	0
Release of restricted stock units	(3,306)	(727)
Net cash provided by financing activities	818,196	41,562
Effect of exchange rate changes on cash and cash equivalents	6,062	23
Net increase (decrease) in cash, cash equivalents and restricted cash	214,061	(454,206)
Cash, cash equivalents and restricted cash, beginning of period	398,554	835,528
Cash, cash equivalents and restricted cash, end of period	612,615	381,322
Supplemental disclosure of non-cash investing activities:
Purchases of property and equipment recorded in accounts payable and accrued expenses	$ 13,719	$ 57