Note 18 - Quarterly Financial Information (Unaudited) - Condensed Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Revenue	$ 11,071	$ 10,420	$ 8,924	$ 16,729	$ 15,366	$ 14,641	$ 14,180	$ 15,096	$ 47,144	$ 59,283
Gross profit	2,205	1,890	1,046	2,585	2,650	2,632	2,423	2,391	7,726	10,096
Loss from operations	(202)	(138)	(1,075)	(439)	(1,377)	(1,129)	(3,929)	(2,879)	(1,854)	(9,314)
Net loss	$ (206)	$ (136)	$ (1,073)	$ (474)	$ (1,360)	$ (1,107)	$ (3,868)	$ (2,846)	$ (1,889)	$ (9,181)
Basic loss per share (in dollars per share)	$ (0.02)	$ (0.01)	$ (0.08)	$ (0.04)	$ (0.10)	$ (0.09)	$ (0.30)	$ (0.22)	$ (0.14)	$ (0.71)
Diluted loss per share (in dollars per share)	$ (0.02)	$ (0.01)	$ (0.08)	$ (0.04)	$ (0.10)	$ (0.09)	$ (0.30)	$ (0.22)	$ (0.14)	$ (0.71)
Basic (in shares)	13,225	13,165	13,110	13,055	12,997	12,934	12,855	12,795	13,139	12,896
Diluted (in shares)	13,225	13,165	13,110	13,055	12,997	12,934	12,855	12,795	13,139	12,896