Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (57,846)	$ (34,440)	$ (25,352)
Adjustments to reconcile net loss to net cash used in operating activities: activities:
Stock-based compensation	5,340	1,933	908
Depreciation	307	318	388
Amortization of premiums on marketable securities	550	152	62
Non-cash lease expense	974
Other	(19)	143	8
Change in operating assets and liabilities:
Prepaid expenses and other assets	38	(2,732)	(275)
Accounts payable	191	(1,230)	1,799
Accrued expenses	3,894	3,117	397
Net cash used in operating activities	(46,571)	(32,739)	(22,065)
Cash flows from investing activities:
Acquisition of property and equipment	(1,349)	(148)	(109)
Purchase of marketable securities	(256,845)	(14,512)	(43,452)
Maturities of marketable securities	114,610	42,571	46,792
Net cash (used in) provided by investing activities	(143,584)	27,911	3,231
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net issuance costs		69,790	61,705
Proceeds from the issuance of common stock, net		223,176
Proceeds from exercise of stock options	2,022	6	100
Net cash provided by financing activities	2,022	292,972	61,805
Net (decrease) increase in cash, cash equivalents, and restricted cash	(188,133)	288,144	42,971
Cash, cash equivalents, and restricted cash—beginning of period	361,422	73,278	30,307
Cash, cash equivalents, and restricted cash—end of period	173,289	361,422	73,278
Supplemental disclosures of noncash investing activities
Lease incentives used for leasehold improvements	(88)
Accrued purchases of property and equipment	1,391
Conversion of convertible preferred stock to common stock		238,723
Conversion of warrant liability to common stock		194
Supplemental disclosures of cash flow information
Cash paid for income tax	$ 23	$ 6	$ 8