Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating activities
Net loss	$ (512,540)	$ (422,773)	$ (145,224)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	11,183	7,795	16,726
Stock-based compensation expense	99,633	102,878	108,102
Net accretion of discounts on marketable securities	(10,253)	(35,117)	(43,952)
Non-cash adjustment to operating lease expense	(4,450)	(4,074)	(3,719)
Right-of-use asset amortization for finance lease	3,629	1,197	0
Non-cash gain from divestiture of small molecule programs	0	(14,537)	0
Other non-cash items	49	0	2
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(540)	(2,480)	(4,094)
Other non-current assets	772	603	0
Accounts payable	(7,520)	1,437	2,431
Accruals and other current liabilities	465	3,248	2,648
Related party contract liability	0	0	(290,532)
Deferred research and development funding liability	6,972	14,129	0
Other non-current liabilities	0	0	(379)
Net cash used in operating activities	(412,600)	(347,694)	(357,991)
Investing activities
Maturities of marketable securities	706,046	1,157,120	2,075,947
Purchases of marketable securities	(441,263)	(1,229,964)	(1,813,700)
Purchases of property and equipment	(9,502)	(15,912)	(12,939)
Net cash provided by (used in) investing activities	255,281	(88,756)	249,308
Financing activities
Proceeds from exercise of awards under equity incentive plans	8,459	17,389	17,820
Payments for finance lease right-of-use asset	(8,168)	(32,338)	0
Issuance costs related to the royalty financing	(324)	0	0
Net cash provided by financing activities	189,216	484,304	17,820
Net increase (decrease) in cash, cash equivalents and restricted cash	31,897	47,854	(90,863)
Cash, cash equivalents and restricted cash at beginning of year	176,535	128,681	219,544
Cash, cash equivalents and restricted cash at end of year	208,432	176,535	128,681
Supplemental disclosures of cash flow information
Equity consideration received in the divestiture of small molecule programs (Note 13)	0	15,000	0
Increase in right-of-use asset due to lessor assets	0	7,051	0
Right-of-use asset obtained in exchange for new finance lease liabilities	0	9,358	0
Property and equipment purchases accrued but not yet paid	0	1,192	553
Cash paid for finance lease interest	720	302	0
Issuance costs incurred but not yet paid	482	0	0
Cash paid during the year for income taxes	46	0	3
Private Placement
Financing activities
Proceeds from issuance / public offering of common stock and pre-funded warrants, net of issuance costs of	0	499,253	0
Public Offering
Financing activities
Proceeds from issuance / public offering of common stock and pre-funded warrants, net of issuance costs of	$ 189,249	$ 0	$ 0