Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net loss	$ (5,822)	$ (6,456)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	32	30
Reduction in the carrying amount of right-of-use assets	144	274
Share-based compensation	623	800
Changes in operating assets and liabilities:
Accounts receivable	(64)	3
Prepaid expenses and other current assets	136	48
Other receivable due from related party	0	56
Accounts payable	425	210
Accrued liabilities and other current liabilities	(87)	(149)
Deferred revenue	(847)	734
Operating lease liability	(98)	(298)
Net cash used in operating activities	(5,558)	(4,748)
Investing activities:
Purchase of property and equipment	(54)	(55)
Net cash used in investing activities	(54)	(55)
Financing activities:
Proceeds from sales of common stock	1,519	2,001
Issuance costs of sale of common stock	(165)	(67)
Proceeds from exercise of common stock options	0	5
Net cash provided by financing activities	1,354	1,939
Net change in cash and cash equivalents	(4,258)	(2,864)
Cash and cash equivalents at beginning of period	12,872	21,407
Cash and cash equivalents at end of period	8,614	18,543
Supplemental disclosure of noncash investing and financing activities:
Unpaid issuance costs of common stock	67	66
Issuance of restricted stock units in lieu of cash bonus obligations	$ 401	$ 393