Note 17 - Quarterly Financial Information (Unaudited) - Condensed Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Revenue	$ 9,078	$ 10,646	$ 10,671	$ 9,972	$ 11,071	$ 10,420	$ 8,924	$ 16,729	$ 40,367	$ 47,144
Gross profit	1,302	1,328	1,192	1,593	2,205	1,890	1,046	2,585	5,415	7,726
Loss from operations	(855)	(866)	(1,321)	(851)	(202)	(138)	(1,075)	(439)	(3,892)	(1,854)
Net loss	$ (780)	$ (895)	$ 293	$ (860)	$ (206)	$ (136)	$ (1,073)	$ (474)	$ (2,242)	$ (1,889)
Basic net (loss) income per share (in dollars per share)	$ (0.04)	$ (0.05)	$ 0.02	$ (0.07)					$ (0.13)	$ (0.14)
Diluted net (loss) income per share (in dollars per share)	$ (0.04)	$ (0.05)	$ 0.02	$ (0.07)					$ (0.13)	$ (0.14)
Basic (in shares)	19,607	19,603	13,332	13,186					16,640	13,139
Diluted (in shares)	19,607	19,603	13,881	13,186					16,640	13,139
Basic and diluted net loss per share (in dollars per share)					$ (0.02)	$ (0.01)	$ (0.08)	$ (0.04)
Basic and diluted (in shares)					13,225	13,165	13,110	13,055