Note 18 - Quarterly Consolidated Financial Data - Quarterly Consolidated Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended														12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[2]	Jun. 30, 2018	[3],[4]	Mar. 31, 2018	[5]	Dec. 31, 2017	[6],[7]	Sep. 30, 2017	[8]	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Net revenues	$ 18,435		$ 20,160		$ 21,097		$ 18,871		$ 19,381		$ 17,352		$ 15,888	$ 14,180	$ 78,563	$ 66,801
Gross margin	9,004		10,092		10,910		9,395		9,745		8,796		8,421	7,728	39,401	34,690
Earnings (loss) before income tax expense	(497)		162		4,396		982		(4,511)		2,841		2,336	3,172	5,043	3,838
Income tax expense	295		728		382		601		55		823		891	1,094	2,006	2,863
Net earnings (loss)	$ (792)		$ (566)		$ 4,014		$ 381		$ (4,566)		$ 2,018		$ 1,445	$ 2,078	$ 3,037	$ 975
Net earnings (loss) per common share – basic (in dollars per share)	$ (0.08)		$ (0.05)		$ 0.39		$ 0.04		$ (0.44)		$ 0.20		$ 0.14	$ 0.20	$ 0.29	$ 0.09
Weighted average common shares outstanding – basic (in shares)	10,367,132		10,355,673		10,342,674		10,326,309		10,308,243		10,288,325		10,277,155	10,264,565	10,347,947	10,284,572
Net earnings (loss) per common share – diluted (in dollars per share)	$ (0.08)		$ (0.05)		$ 0.39		$ 0.04		$ (0.44)		$ 0.19		$ 0.14	$ 0.20	$ 0.29	$ 0.09
Weighted average common shares outstanding – diluted (in shares)	10,367,132		10,355,673		10,370,318		10,365,306		10,308,243		10,351,009		10,334,894	10,295,337	10,382,194	10,339,313

[1] The quarter ended December 31, 2018 includes a $2,828 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[2] The quarter ended September 30, 2018 includes $3,057 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[3] The quarter ended June 30, 2018 includes a $710 reduction in the fair value of contingent consideration, which was not taxable.

[4] The quarter ended June 30, 2018 includes the reversal of certain adjustments originally recorded in the quarter ended December 31, 2017 which were related to tax legislation enacted in December 2017, as discussed in Notes 2 and 12.

[5] The quarter ended March 31, 2018 includes a $1,726 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[6] The quarter ended December 31, 2017 includes a $7,525 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[7] The quarter ended December 31, 2017 includes adjustments related to tax legislation enacted in December 2017, as discussed in Note 2 and 12.

[8] The quarter ended September 30, 2017 includes a $549 reduction in the fair value of contingent consideration, which was not taxable.