CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (50,647)	$ (27,674)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation expense	1,039	363
Non-cash lease expense	2,260	461
Stock-based compensation	3,112	748
Other	38
Changes in operating assets and liabilities:
Operating lease liability	(1,840)	545
Prepaid expenses and other current assets	(5,537)	(847)
Accounts payable and accrued expenses	333	3,746
Other assets	(315)
Net cash used in operating activities	(51,557)	(22,658)
Cash flow from investing activities
Purchases of investments	(82,972)
Purchases of property and equipment	(2,726)	(2,684)
Net cash used in investing activities	(85,698)	(2,684)
Cash flow from financing activities
Proceeds from issuance of redeemable convertible preferred stock	45,375	82,267
Proceeds from the issuance of common stock upon closing of initial public offering, net of underwriter fees	189,199
Payment of initial public offering costs	(2,215)
Proceeds from stock option exercises	245	213
Net cash provided by financing activities	232,604	82,480
Net increase in cash, cash equivalents and restricted cash equivalents	95,349	57,138
Cash, cash equivalents and restricted cash equivalents, beginning of period	50,098	8,025
Cash, cash equivalents and restricted cash equivalents, end of period	145,447	65,163
Supplemental disclosure of non-cash activities
Lease incentive paid by the landlord on behalf of the Company		151
Operating right-of-use assets and operating lease liability recorded upon lease commencement	35	17,899
Purchases of property and equipment in accounts payable	18	599
Conversion of redeemable convertible preferred stock to common stock upon closing of the initial public offering	$ 152,711
Deferred offering costs in accounts payable and accrued expenses		$ 355