Condensed Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (34,235)	$ (23,844)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	314	108
Stock-based compensation expense	6,238	3,701
Amortization of premiums and discounts on marketable securities, net	164	40
Gain on disposal of property and equipment	0	(16)
Changes in operating assets and liabilities:
Prepaid and other assets	(2,080)	(491)
Accounts payable and accrued liabilities	4,957	2,390
Accrued compensation	(4,699)	(407)
Operating lease right-of-use assets and liabilities, net	689	150
Deferred revenue	(922)	(1,312)
Net cash used in operating activities	(29,574)	(19,681)
Cash flows from investing activities
Purchases of marketable securities	(174,717)	0
Purchases of property and equipment	(758)	(525)
Net cash used in investing activities	(175,475)	(525)
Cash flows from financing activities
Proceeds from issuance of common stock in public offerings, gross	24,848	0
Payment of issuance costs related to public offerings	(745)	0
Proceeds from exercise of stock options	10	17
Net cash provided by financing activities	24,113	17
Net decrease in cash, cash equivalents and restricted cash	(180,936)	(20,189)
Cash, cash equivalents and restricted cash at beginning of period	320,699	321,713
Cash, cash equivalents and restricted cash at end of period	139,763	301,524
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	0	286
Receivables from stock option exercises included in prepaid and other assets	$ 0	$ 7