Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Allowance for doubtful accounts	$ 26	$ 103
Accrued liabilities	357	412
Net operating loss carryforwards	26,478	24,798
Intangible assets	3,883	4,259
Share-based compensation expense	365	228
Other	1,418	1,370
Total gross deferred tax assets	32,527	31,181
Valuation allowance	(31,979)	(30,447)
Total deferred tax assets	548	734
Right of use assets	(509)	(733)
Fixed assets	(39)	0
Other	0	(1)
Total gross deferred tax liabilities	(548)	(734)
Net deferred tax assets	$ 0	$ 0