Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net loss	$ (60,692)	$ (33,277)
Adjustments to reconcile net loss used in operating activities:
Stock-based compensation	11,557	5,622
Depreciation and amortization	1,306	785
Amortization of right-of-use asset	971	1,036
Loss on disposal of property and equipment	0	180
Write-off of right-of-use asset upon lease termination	0	113
Changes in operating assets and liabilities:
Other current assets and non-current assets	129	(2,481)
Accounts payable and accrued liabilities	(142)	3,018
Operating lease right-of-use assets	0	(169)
Operating lease liabilities	(687)	598
Net cash used in operating activities	(47,558)	(24,575)
Investing activities
Purchases of property and equipment	(3,263)	(2,219)
Net cash used in investing activities	(3,263)	(2,219)
Financing activities
Proceeds from issuance of common stock and pre-funded warrants, net of commissions of $4.6 million	0	71,675
Payment of offering costs	0	(355)
Proceeds from exercise of stock options	411	5,665
Proceeds from issuance of common stock under Employee Stock Purchase Plan	372	199
Payment on finance lease obligations	(51)	(49)
Net cash provided by financing activities	732	77,135
Net change in cash, cash equivalents, and restricted cash during the year	(50,089)	50,341
Cash, cash equivalents, and restricted cash at beginning of year	193,434	143,093
Cash, cash equivalents, and restricted cash at end of year	143,345	193,434
Supplemental disclosure of non-cash investing and financing activities:
Operating lease liabilities arising from obtaining right-of-use asset	1,584	10,364
Purchase of property and equipment unpaid at period end	$ 412	$ 36