Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (100,217)	$ (45,593)	$ (41,246)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	24,972	5,190	1,196
Depreciation and amortization	2,397	1,763	825
Premiums and discounts on available-for-sale marketable securities	5,807	1,571
Loss on disposal of property and equipment	18
Non-cash research and development expense		332	443
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(4,016)	(3,816)	(564)
Accounts receivable—due from related party	577	(577)
Contract asset due from related party	721	(856)
Other receivables due from related party			148
Accounts payable	54	990	904
Accrued expenses and other current liabilities	12,599	5,754	2,248
Deferred revenue	(69,356)	117,400	52,991
Operating lease right-of-use assets	419	8,444	1,350
Operating lease liabilities	(1,015)	(2,647)	(383)
Other non-current assets	(1,992)	(30)
Other non-current liabilities	86	205	(7)
Net cash (used in) provided by operating activities	(128,946)	88,130	17,905
Investing activities
Purchase of property and equipment, net	(1,597)	(9,096)	(532)
Purchase of marketable securities	(456,404)	(529,382)	(15,954)
Maturities of marketable securities	358,166	115,890
Net cash used in investing activities	(99,835)	(422,588)	(16,486)
Financing activities
Proceeds from stock option exercises	7,632	162	74
Proceeds from employee stock purchase plan	788
Payments of offering costs in connection with initial public offering	(397)
Payments on financing leases	(849)	(554)	(371)
Proceeds from follow on offering, net of underwriting discounts and offering costs	240,760
Proceeds from initial public offering, net of underwriting discounts and offering costs		183,146
Proceeds from concurrent private placement	2,346	13,527
Net cash provided by financing activities	250,280	289,262	34,911
Net increase (decrease) in cash, cash equivalents and restricted cash	21,499	(45,196)	36,330
Cash, cash equivalents and restricted cash at beginning of period	32,593	77,789	41,459
Cash, cash equivalents and restricted cash at end of period	54,092	32,593	77,789
Supplemental disclosure of cash flow activities
Cash paid for interest	158	115	46
Supplemental disclosure of noncash investing and financing activities
Purchases of property and equipment through finance and lease liabilities	1,918		1,642
Property and equipment purchases included in accounts payable and accrued expenses	42	27	315
Offering costs included in accounts payable		397
Supplemental disclosure of noncash operating activities
Right-of-use assets obtained in exchange for operating lease liabilities			16,522
Tenant improvement receivable included in other assets			287
Reduction of right-of-use asset and liability due to lease modification		2,161
Cash and cash equivalents	47,976	31,004	76,015
Restricted cash	6,116	1,589	1,774
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total	54,092	32,593	77,789
Series B Convertible Preferred Stock
Financing activities
Proceeds from the issuance of Convertible Preferred Stock, net of issuance costs			21,183
Series B-1 Convertible Preferred
Financing activities
Proceeds from the issuance of Convertible Preferred Stock, net of issuance costs		4,800	14,025
Series C Convertible Preferred Stock
Financing activities
Proceeds from the issuance of Convertible Preferred Stock, net of issuance costs		$ 88,181