Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (2,655)	$ (2,223)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	13	14
Amortization of operating lease right-of-use assets	95	75
Share-based compensation expense	56	52
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(707)	(588)
Accounts payable	294	159
Operating lease liability	(87)	(79)
Accrued expenses and other liabilities	(838)	(645)
Net cash used in operating activities	(3,829)	(3,235)
Cash flows from investing activities:
Purchases of property and equipment	(26)
Net cash used in investing activities	(26)
Cash flows from financing activities:
Proceeds from exercise of warrants		8,509
Net cash provided by financing activities		8,509
(Decrease) / Increase in cash and cash equivalents and restricted cash	(3,855)	5,274
Cash, cash equivalents and restricted cash at beginning of period	19,181	19,603
Cash, cash equivalents and restricted cash at end of period	$ 15,326	$ 24,877