Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities
Net loss	$ (101,802)	$ (109,781)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,162	10,047
Stock–based compensation expense	27,840	28,084
Net amortization of premiums and (discounts) on marketable securities	(10,516)	(7,853)
Non-cash adjustment to operating lease expense	(957)	(877)
Non-cash gain from divestiture of small molecule programs	(14,537)	0
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(18,766)	(1,789)
Accounts payable	635	3,698
Accruals and other current liabilities	2,321	19,810
Related-party contract liability	0	(141)
Net cash used in operating activities	(113,620)	(58,802)
Investing activities
Purchases of marketable securities	(834,157)	(523,714)
Purchases of property and equipment	(2,150)	(2,786)
Maturities and sales of marketable securities	383,120	433,785
Net cash used in investing activities	(453,187)	(92,715)
Financing activities
Proceeds from Issuance of Common Stock	499,253	0
Proceeds from exercise of awards under equity incentive plans	1,022	1,604
Net cash provided by financing activities	500,275	1,604
Net decrease in cash, cash equivalents and restricted cash	(66,532)	(149,913)
Cash, cash equivalents and restricted cash at beginning of period	128,681	219,544
Cash, cash equivalents and restricted cash at end of period	62,149	69,631
Supplemental disclosures of cash flow information
Cash paid during the period for income taxes	0	4
Equity consideration received in the divestiture of small molecule programs (Note 10)	15,000	0
Property and equipment purchases accrued but not yet paid	1,947	6,075
Issuance costs incurred but not yet paid	$ 394	$ 0