Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
OPERATING ACTIVITIES:
Net loss	$ (244,166)	$ (266,759)	$ (283,255)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	12,750	15,500	17,543
Stock-based compensation expense	25,464	37,678	35,533
Change in the estimated fair value of contingent consideration	14,750	(638)	(40,773)
Change in the estimated fair value of success payment liabilities	14,682	(8,243)	(8,208)
Non-cash expense for operating lease right-of-use assets	9,171	9,681	13,265
Impairment of long-lived assets	44,611	1,891	7,014
Other non-cash items, net	(10,976)	(11,078)	(13,312)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	1,165	(3,513)	8,143
Operating lease right-of-use assets and liabilities	(2,997)	9,341	10,959
Accounts payable	(3,545)	1,377	1,027
Accrued expenses and other liabilities	(4,737)	(8,390)	(1,518)
Net cash used in operating activities	(143,828)	(223,153)	(253,582)
INVESTING ACTIVITIES:
Purchases of marketable securities	(87,293)	(226,064)	(157,744)
Proceeds from maturities of marketable securities	46,561	276,947	349,788
Purchases of property and equipment	(938)	(33,430)	(20,032)
Proceeds from disposal of assets	1,432	0	0
Net cash provided by (used in) investing activities	(40,238)	17,453	172,012
FINANCING ACTIVITIES:
Proceeds from employee stock purchase plan and exercise of stock options	2,676	11,005	4,626
Proceeds related to common stock financings, net	126,404	181,000	27,020
Proceeds (principal payments), net for tenant improvement loan	(347)	7,744	0
Net cash provided by financing activities	128,733	199,749	31,646
Net decrease in cash, cash equivalents, and restricted cash	(55,333)	(5,951)	(49,924)
Cash, cash equivalents, and restricted cash at beginning of period	131,398	137,349	187,273
Cash, cash equivalents, and restricted cash at end of period	76,065	131,398	137,349
RECONCILITION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	71,870	127,566	133,517
Restricted cash	4,195	3,832	3,832
Total cash, cash equivalents, and restricted cash	76,065	131,398	137,349
SUPPLEMENTAL CASH FLOW INFORMATION:
Operating lease right-of-use assets obtained in exchange for lease obligations	0	0	8,984
Purchases of property and equipment included in accounts payable and accrued liabilities	0	0	9,471
Cash received for tenant improvement allowances	891	7,509	12,547
Derecognition of operating lease right-of-use assets for lease termination and modification	$ (2,724)	$ (7,261)	$ (14,204)