Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net loss	$ (154,808)	$ (100,217)	$ (45,593)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	35,480	24,972	5,190
Depreciation and amortization	2,977	2,397	1,763
Premiums and discounts on available for sale marketable securities	889	5,807	1,571
Loss on disposal of property and equipment	0	18	0
Non-cash research and development expense	0	0	332
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(992)	(4,016)	(3,816)
Accounts receivable due from related party	0	577	(577)
Contract asset-due from related party	(2,401)	721	(856)
Accounts payable	253	54	990
Accrued expenses and other current liabilities	4,519	12,599	5,754
Deferred revenue	(37,774)	(69,356)	117,400
Operating lease right-of-use assets	517	419	8,444
Operating lease liabilities	(1,004)	(1,015)	(2,647)
Other non-current assets	(998)	(1,992)	(30)
Other non-current liabilities	257	86	205
Net cash (used in) provided by operating activities	(153,085)	(128,946)	88,130
Investing activities
Purchase of property and equipment, net	(2,836)	(1,597)	(9,096)
Purchase of marketable securities	(445,972)	(456,404)	(529,382)
Maturities of marketable securities	469,327	358,166	115,890
Net cash provided by (used in) investing activities	20,519	(99,835)	(422,588)
Financing activities
Proceeds from issuance of common stock and accompanying pre-funded warrants from private placement, net of issuance costs	149,825	0	0
Proceeds from stock option exercises	3,154	7,632	162
Proceeds from employee stock purchase plan	1,150	788	0
Payments of offering costs in connection with initial public offering		(397)
Payments on financing leases	(1,130)	(849)	(554)
Proceeds from follow-on public offering, net of underwriting discounts and offering costs	0	240,760	0
Proceeds from initial public offering, net of underwriting discounts and offering costs	0	0	183,146
Proceeds from concurrent private placement	0	2,346	13,527
Net cash provided by financing activities	152,999	250,280	289,262
Net increase (decrease) in cash, cash equivalents and restricted cash	20,433	21,499	(45,196)
Cash, cash equivalents and restricted cash at beginning of period	54,092	32,593	77,789
Cash, cash equivalents and restricted cash at end of period	74,525	54,092	32,593
Supplemental disclosure of cash flow activities
Cash paid for interest	179	158	115
Supplemental disclosure of noncash investing and financing activities
Purchases of property and equipment through finance and lease liabilities	1,506	1,918	0
Property and equipment purchases included in accounts payable and accrued expenses	87	42	27
Offering costs included in accounts payable	0	0	397
Supplemental disclosure of noncash operating activities
Reduction of right-of-use asset and liability due to lease modification	0	0	2,161
Cash and cash equivalents	68,395	47,976	31,004
Restricted cash	6,130	6,116	1,589
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total	74,525	54,092	32,593
Series B-1 Convertible Preferred
Financing activities
Proceeds from the issuance of Convertible Preferred Stock, net of issuance costs	0	0	4,800
Series C Convertible Preferred Stock
Financing activities
Proceeds from the issuance of Convertible Preferred Stock, net of issuance costs	$ 0	$ 0	$ 88,181