Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 9,930	$ 12,872
Accounts receivable, net of allowance for doubtful accounts of $13 and $22 as of March 31, 2022 and December 31, 2021	326	147
Prepaid expenses and other current assets	405	462
Total current assets	10,661	13,481
Property and equipment, net	195	182
Operating lease right-of-use asset, net	1,812	1,883
Other assets	172	172
Total assets	12,840	15,718
Current liabilities:
Accounts payable	764	507
Accrued expenses and other current liabilities	1,920	2,121
Deferred revenue	948	847
Operating lease liability - current	281	237
Total current liabilities	3,913	3,712
Operating lease liability - noncurrent	1,558	1,631
Total liabilities	5,471	5,343
Commitments and contingencies (Notes 1, 2, 5 and 12)
Stockholders’ equity:
Preferred stock, $0.001 par value, 25,000,000 shares authorized and no shares issued and outstanding as of March 31, 2022 and December 31, 2021	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized 16,871,265 shares issued and outstanding as of March 31, 2022 and December 31, 2021	17	17
Additional paid-in capital	139,374	139,055
Accumulated deficit	(132,022)	(128,697)
Total stockholders’ equity	7,369	10,375
Total liabilities and stockholders’ equity	$ 12,840	$ 15,718