Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net loss	$ (223,858)	$ (146,962)	$ (154,808)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	55,012	43,118	35,480
Lease impairment charge	4,925	0	0
Depreciation and amortization	7,373	3,565	2,977
Premiums and discounts on available for sale marketable securities	(13,983)	(5,229)	889
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(8,903)	(1,961)	(992)
Accounts receivable	15,000	(15,000)	0
Contract asset	2,815	(1,226)	(2,401)
Accounts payable	(307)	2,038	253
Accrued expenses and other current liabilities	4,180	3,180	4,519
Deferred revenue	(41,075)	(8,609)	(37,774)
Operating lease right-of-use assets	2,541	4,797	517
Operating lease liabilities	1,921	18,582	(1,004)
Other non-current assets	168	909	(998)
Other non-current liabilities	(310)	(28)	257
Net cash used in operating activities	(194,501)	(102,826)	(153,085)
Investing activities
Purchase of property and equipment, net	(12,838)	(34,480)	(2,836)
Purchase of marketable securities	(901,226)	(189,151)	(445,972)
Maturities of marketable securities	509,987	363,517	469,327
Net cash provided by (used in) investing activities	(404,077)	139,886	20,519
Financing activities
Issuance of common stock and accompanying pre-funded warrants from January 2024 public offering, net of issuance costs of $14.9 million	301,373	0	0
Proceeds from issuance of common stock through At-The Market Sales Agreement, net of issuance costs of $1.2 million	48,740	0	0
Issuance of common stock and accompanying pre-funded warrants from August 2024 public offering, net of issuance costs of $12.2 million	246,506	0	0
Proceeds from 2022 issuance of common stock and accompanying pre-funded warrants from private placement, net of issuance costs of $0.2 million	0	0	149,825
Proceeds from stock option exercises	11,790	2,860	3,154
Proceeds from employee stock purchase plan	2,018	1,408	1,150
Payments on financing leases	(1,576)	(76)	(1,130)
Net cash provided by financing activities	608,851	4,192	152,999
Net increase (decrease) in cash, cash equivalents and restricted cash	10,273	41,252	20,433
Cash, cash equivalents and restricted cash at beginning of period	115,777	74,525	54,092
Cash, cash equivalents and restricted cash at end of period	126,050	115,777	74,525
Supplemental disclosure of cash flow activities
Right-of-use assets obtained in exchange for operating lease liabilities	0	48,833	0
Cash paid for interest	206	162	179
Supplemental disclosure of noncash investing and financing activities
Purchases of property and equipment through finance and lease liabilities	2,742	0	1,506
Property and equipment purchases included in accounts payable and accrued expenses	60	4,016	87
Cash and cash equivalents	120,256	109,966	68,395
Restricted cash	5,794	5,811	6,130
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total	$ 126,050	$ 115,777	$ 74,525