Condensed Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net loss	$ (37,672)	$ (78,487)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Stock-based compensation expense	5,364	4,473
Depreciation and amortization	1,152	1,098
Non-cash lease expense	329	160
Net amortization of discounts on marketable securities	446	1,168
Changes in operating assets and liabilities
Prepaid expenses and other assets	(1,287)	(937)
Other assets	(10)	382
Accounts payable	125	426
Accrued liabilities	(290)	2,500
Deferred revenue	(14,209)	(14,846)
Operating lease liabilities	(789)	(580)
Net cash used in operating activities	(46,841)	(84,643)
Cash flows from investing activities
Purchases of property and equipment	(53)	(45)
Purchases of marketable securities	(11,509)	(100,469)
Maturities of marketable securities	81,402	130,304
Net cash provided by investing activities	69,840	29,790
Cash flows from financing activities
Proceeds from follow-on offering, net of issuance costs	0	107,581
Proceeds from issuance of common stock in connection with employee benefit plans	882	748
Proceeds from issuance of common stock, net of issuance cost	0	2,767
Net cash provided by financing activities	882	111,096
Net increase in cash, cash equivalents, and restricted cash	23,881	56,243
Cash, cash equivalents, and restricted cash at beginning of period	45,360	21,637
Cash, cash equivalents, and restricted cash at end of period	69,241	77,880
Supplemental disclosures of non-cash investing and financing information
Purchases of property and equipment included in accrued liabilities and accounts payable	98	0
Reclassification of employee stock liability to equity upon vesting	6	12
Deferred offering costs included in accounts payable and accrued liabilities	$ 0	$ 8