CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES
Net loss	$ (7,978)	$ (4,865)
Adjustments to reconcile net loss to net cash used in operating activities:
Forgiveness of notes payable	(408)	0
Share-based compensation expense	980	1,144
Depreciation	107	184
Change in fair value of warrant liability	(15)	(16)
Changes in operating assets and liabilities:
Grant receivable	77	(77)
Prepaid expenses and other current assets	229	(80)
Accounts payable	645	(210)
Accrued and other current liabilities	485	(121)
Accrual for contingency matter	3,250	0
Net cash used in operating activities	(2,628)	(4,041)
INVESTING ACTIVITIES
Purchases of property, plant and equipment	0	(7)
Net cash used in investing activities	0	(7)
FINANCING ACTIVITIES
Proceeds from issuance of common stock and warrants	2,844	1,058
Proceeds from exercise of warrants	0	2,741
Proceeds from notes payable	0	404
Acquisition of common stock for tax withholding obligations	0	(42)
Net cash provided by financing activities	2,844	4,161
Net increase in cash and restricted cash	216	113
Cash and restricted cash at the beginning of the year	1,076	963
Cash and restricted cash at the end of the year	1,292	1,076
Supplemental disclosure of non-cash investing and financing activities:
Issuance of vested common stock	0	42
Supplemental disclosure of non-cash operating activities:
Increase of right-of-use asset and liability due to lease extension	$ 94	$ 94