Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss	$ (11,907)	$ (12,623)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	82	60
Reduction in the carrying amount of right-of-use assets	295	580
Share-based compensation	1,183	1,661
Loss on disposal of property and equipment	0	19
Changes in operating assets and liabilities:
Accounts receivable	(54)	85
Prepaid expenses and other current assets	163	(179)
Other receivable due from related party	0	618
Accounts payable	4	(239)
Accrued expenses and other current liabilities	416	130
Deferred revenue	(506)	164
Operating lease liability	(237)	(642)
Net cash used in operating activities	(10,561)	(10,366)
Investing activities:
Purchase of property and equipment	(70)	(116)
Net cash used in investing activities	(70)	(116)
Financing activities:
Proceeds from sales of common stock	5,540	2,001
Issuance costs of sale of common stock	(418)	(59)
Proceeds from exercise of common stock options	0	5
Net cash provided by financing activities	5,122	1,947
Net change in cash and cash equivalents	(5,509)	(8,535)
Cash and cash equivalents at beginning of year	12,872	21,407
Cash and cash equivalents at end of year	7,363	12,872
Supplemental disclosure of noncash investing and financing activities:
Unpaid issuance costs of common stock	172	0
Issuance of restricted stock units in lieu of cash bonus obligations	401	393
Right-of-use asset obtained in exchange for lease obligation	$ 0	$ 1,896