Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
OPERATING ACTIVITIES:
Net loss	$ (283,255)	$ (269,476)	$ (355,928)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and impairment of long-lived assets	24,557	15,625	11,070
Stock-based compensation expense	35,533	38,337	22,362
Change in the estimated fair value of contingent consideration	(40,773)	(3,364)	31,842
Change in the estimated fair value of success payment liabilities	(8,208)	(81,518)	26,031
Non-cash expense for operating lease right-of-use assets	13,265	12,106	6,844
Other non-cash items, net	(13,312)	(9,302)	(3,076)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	8,143	(5,988)	(861)
Operating lease right-of-use assets and liabilities	10,959	1,562	5,088
Accounts payable	1,027	1,058	(266)
Accrued expenses and other liabilities	(1,518)	10,910	5,840
Net cash used in operating activities	(253,582)	(290,050)	(251,054)
INVESTING ACTIVITIES:
Purchases of marketable securities	(157,744)	(78,688)	(491,387)
Proceeds from maturities of marketable securities	349,788	310,126	280,025
Purchases of property and equipment	(20,032)	(20,876)	(29,862)
Other investing activities			(4,574)
Net cash provided by (used in) investing activities	172,012	210,562	(245,798)
FINANCING ACTIVITIES:
Proceeds from initial public offering, net of issuance costs			626,405
Proceeds from issuance of common stock, net	4,626	4,312	5,346
Net cash provided by financing activities	31,646	4,913	631,751
Net increase (decrease) in cash, cash equivalents, and restricted cash	(49,924)	(74,575)	134,899
Cash, cash equivalents, and restricted cash at beginning of period	187,273	261,848	126,949
Cash, cash equivalents, and restricted cash at end of period	137,349	187,273	261,848
RECONCILITION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	133,517	176,765	253,029
Restricted cash	3,832	6,100
Long-term restricted cash		4,408	8,819
Total cash, cash equivalents, and restricted cash	137,349	187,273	261,848
SUPPLEMENTAL CASH FLOW INFORMATION:
Operating lease right-of-use assets obtained in exchange for lease obligations	8,984	21,073	39,996
Purchases of property and equipment included in accounts payable and accrued liabilities	9,471	1,234	3,015
Cash received for tenant improvement allowances	12,547	2,014	$ 5,445
Remeasurement of operating lease right-of-use asset for lease modification		(12,801)
Derecognition of operating lease right-of-use asset for lease termination	(14,204)
At The Market Offering
FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net	$ 27,020	$ 601