Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (30,910)	$ (24,639)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,963	1,954
Noncash lease expense	288	283
Stock-based compensation expense	3,276	1,500
Change in fair value of stock warrants	(508)	(11,637)
Change in fair value of contingent consideration	(731)	4,340
Change in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	(139)	(549)
Accounts payable	(235)	1,494
Accrued compensation	(277)	722
Accrued clinical trial site costs	(369)	1,790
Operating lease liabilities	(263)	(305)
Other liabilities	135	(177)
Net cash used in operating activities	(27,770)	(25,224)
Cash flows from investing activities:
Purchases of property and equipment	(22)	(7)
Net cash used in investing activities	(22)	(7)
Cash flows from financing activities:
Proceeds from sale of common stock and common stock warrants, net of costs		53,722
Tax withholding payments for net share-settled equity awards	(120)
Proceeds from stock option exercises		17
Principal paid on finance lease liabilities	(8)	(17)
Net cash (used in) provided by financing activities	(128)	53,722
Net (decrease) increase in cash and cash equivalents	(27,920)	28,491
Cash and cash equivalents, beginning of period	49,224	20,733
Cash and cash equivalents, end of period	21,304	49,224
Supplemental disclosure of non-cash investing and financing information
Right-of use assets obtained in exchange for operating lease obligations	$ 581
Purchases of property and equipment in accounts payable		$ 1