Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (44,112)	$ (45,525)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	6,789	8,548
Depreciation and amortization	1,193	916
Amortization of operating lease right-of-use assets	776	730
Amortization and accretion of premiums/discounts on available-for-sale securities	(105)	0
Loss on disposal of property and equipment	108	0
Changes in operating assets and liabilities:
Other current assets and other non-current assets	(287)	36
Accounts payable and accrued liabilities	1,823	332
Operating lease liabilities	(859)	(427)
Net cash used in operating activities	(34,674)	(35,390)
Investing activities
Purchases of property and equipment	(1,006)	(2,867)
Purchases of available-for-sale securities	(81,595)	0
Proceeds from maturities of available-for-sale securities	15,000	0
Net cash used in investing activities	(67,601)	(2,867)
Financing activities
Proceeds from exercise of stock options	134	408
Payment on finance lease obligations	(54)	(2)
Proceeds from the issuance of common stock under Employee Stock Purchase Plan	63	219
Net cash provided by financing activities	143	625
Net change in cash, cash equivalents, and restricted cash during the period	(102,132)	(37,632)
Cash, cash equivalents, and restricted cash, beginning of period	143,345	193,434
Cash, cash equivalents, and restricted cash, end of period	41,213	155,802
Supplemental disclosure of non-cash investing and financing activities:
Operating lease liabilities arising from obtaining ROU asset	0	1,584
Purchases of property and equipment unpaid at period-end	$ 28	$ 297