Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net loss	$ (31,534)	$ (15,109)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	443	493
Stock-based compensation expense	1,345	1,045
Warrant issuance costs	123
Warrant liability fair value adjustment	(1,410)	(0)
Changes in assets and liabilities
Prepaid expenses and other assets	(1,138)	(3,117)
Accounts payable	2,043	1,101
Deferred revenue	(2,707)	2,010
Accrued and other liabilities	924	(1,594)
Net cash used in operating activities	(31,911)	(15,171)
Cash flows from financing activities
Proceeds from issuance of common stock in connection with employee benefit plans	26	71
Proceeds from issuance of common stock in connection with exercise of options	0	280
Proceeds from issuance of common stock and common stock warrants in direct offering, net of issuance costs	19,171	20,866
Net cash provided by financing activities	19,320	30,067
Net change in cash, cash equivalents, and restricted cash	(12,591)	14,896
Cash, cash equivalents, and restricted cash at beginning of period	61,855	62,971
Cash, cash equivalents, and restricted cash at end of period	49,264	77,867
Supplemental disclosure of noncash items
Reclass to additional paid-in-capital upon exercise	8,590	0
At-the-market Offering [Member]
Cash flows from financing activities
Proceeds from issuance of common stock in at the market offering	$ 123	$ 8,850