Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Cash flows from operating activities:
Net loss	$ (212,394)	$ (292,963)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,466	1,567
Amortization of right-of-use asset	489	535
Accretion of discounts on marketable securities	(2,839)	(2,899)
Share-based compensation expense	25,690	15,748
Loss on disposal of property and equipment	896	0
Charge for purchase of in-process research and development assets, including upon achievement of milestones	10,000	152,344
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(3,489)	906
Accounts payable	(9,164)	9,526
Accrued expenses and other current liabilities	4,533	13,550
Deferred revenue	(6,941)	(9,041)
Operating lease liabilities	(166)	(67)
Net cash used in operating activities	(190,919)	(110,794)
Cash flows from investing activities:
Maturities of marketable securities	200,000	155,000
Purchases of marketable securities	(123,266)	(186,555)
Purchases of property and equipment	(9,685)	(7,173)
Purchases of in-process research and development assets	(6,246)	(46,335)
Net cash provided by (used in) investing activities	60,803	(85,063)
Cash flows from financing activities:
Proceeds from public offerings	633,003	230,002
Proceeds from issuance of common stock under ATM	45,897	20,000
Payment of offering costs	(39,456)	(15,228)
Proceeds from exercise of stock options	913	2,024
Proceeds from exercise of common stock warrants	0	3,731
Net cash provided by financing activities	640,357	240,529
Net increase in cash and cash equivalents and restricted cash	510,241	44,672
Cash and cash equivalents and restricted cash at beginning of period	143,451	98,779
Cash and cash equivalents and restricted cash at end of period	653,692	143,451
Reconciliation of cash and cash equivalents and restricted cash:
Cash and cash equivalents	653,482	143,351
Restricted cash	210	100
Total cash, cash equivalents, and restricted cash	653,692	143,451
Supplemental disclosures of non-cash investing and financing activities:
Purchases of in-process research and development assets, including payments owed upon achievement of development milestones, in accounts payable and accrued expenses	10,000	6,246
Purchases of property and equipment in accounts payable and accrued expenses and other current liabilities	1,006	2,806
Remeasurement of operating right-of-use asset and lease liability due to lease modifications	811	2,035
Offering costs in accounts payable and accrued expenses and other current liabilities	364	0
Issuance of common stock in exchange for in-process research and development assets		97,722
Net liabilities assumed from purchases of in-process research and development assets	0	2,041
Right-of-use assets obtained in exchange for operating lease liabilities	$ 0	$ 1,189