Condensed Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities
Net loss	$ (52,394)	$ (34,235)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	391	314
Stock-based compensation expense	9,104	6,238
Amortization of premiums and discounts on marketable securities, net	(2,231)	164
Non-cash operating lease costs	688	689
Changes in operating assets and liabilities:
Prepaid and other assets	1,491	(2,080)
Accounts payable and accrued liabilities	1,158	4,957
Accrued compensation	(5,181)	(4,699)
Operating lease liabilities	(774)	0
Deferred revenue	(1,219)	(922)
Net cash used in operating activities	(48,967)	(29,574)
Cash flows from investing activities
Maturities of marketable securities	57,490	0
Purchases of marketable securities	(251,350)	(174,717)
Purchases of property and equipment	(1,820)	(758)
Net cash used in investing activities	(195,680)	(175,475)
Cash flows from financing activities
Proceeds from issuance of common stock in public offerings, net of issuance costs	22,441	24,103
Proceeds from issuance of common stock under employee incentive equity plans	520	10
Net cash provided by financing activities	22,961	24,113
Net decrease in cash, cash equivalents and restricted cash	(221,686)	(180,936)
Cash, cash equivalents and restricted cash at beginning of period	340,647	320,699
Cash, cash equivalents and restricted cash at end of period	118,961	139,763
Supplemental schedule of noncash investing and financing activities:
Costs incurred, but not paid, in connection with purchases of property and equipment included in accounts payable and accrued liabilities	$ 162	$ 0