Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (112,961)	$ (58,655)	$ (49,762)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	2,476	2,101	1,725
Net amortization (accretion) of premiums (discounts) on marketable securities	(11,553)	(695)	1,834
Stock-based compensation	18,489	11,629	8,237
Amortization of right of use assets	1,532	1,414	1,307
Changes in assets and liabilities
Accounts receivable	193	892	774
Prepaid expenses and other assets	(2,045)	(2,119)	(189)
Accounts payable	2,635	1,864	1,166
Accrued and other liabilities	1,635	4,572	4,212
Contract liabilities	(13,753)	(46,479)	(23,541)
Lease liabilities	(1,872)	(1,699)	(1,542)
Net cash used in operating activities	(115,224)	(87,175)	(55,779)
Cash flows from investing activities
Purchases of property and equipment, net	(2,368)	(3,443)	(2,644)
Purchases of marketable securities	(595,980)	(255,808)	(314,996)
Maturities of marketable securities	439,892	225,847	243,956
Sales of marketable securities	0	0	4,018
Net cash used in investing activities	(158,456)	(33,404)	(69,666)
Cash flows from financing activities
Proceeds from issuance of common stock in public offering, net of issuance costs	281,165	86,105	85,990
Proceeds from issuances of pre-funded warrants	42,182	0	0
Proceeds from issuance of common stock related to at-the-market offering program, net of issuance costs	28,598	8,857	57,263
Proceeds from exercise of common stock options, net of repurchases	9,559	1,448	1,504
Proceeds from ESPP purchases	1,213	755	697
Net cash provided by financing activities	362,717	97,165	145,454
Net increase (decrease) in cash, cash equivalents and restricted cash	89,037	(23,414)	20,009
Cash, cash equivalents and restricted cash, at beginning of period	68,738	92,152	72,143
Cash, cash equivalents and restricted cash, at end of period	157,775	68,738	92,152
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	157,018	68,632	92,046
Restricted cash	757	106	106
Cash, cash equivalents and restricted cash	157,775	68,738	92,152
Supplemental disclosure of cash flow information:
Cash paid for income taxes	0	0	4
Cash paid for interest	69	60	71
Supplemental non-cash investing and financing activities:
Vesting of early exercised options and restricted stock	0	0	24
Purchases of property and equipment in accounts payable and accrued liabilities	147	384	92
Right-of-use asset obtained in exchange for a new operating lease liability	1,294	0	0
Unpaid offering costs	$ 43	$ 39	$ 0