Note 10 - Segment Information - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net revenues	$ 58,388	$ 48,752	$ 172,191	$ 131,361
Operating income (loss)	2,324	828	1,817	2,284
Interest expense	333	110	886	117
Other income, net	(109)	(78)	(413)	(275)
Income before income tax expense	2,100	796	1,344	2,442
Income tax expense	419	210	335	907
Net income	1,681	586	1,009	1,535
Depreciation and amortization	522	487	1,595	1,526
Capital expenditures	389	355	1,340	1,046
US Segment [Member]
Net revenues	22,413	15,062	62,338	40,069
Operating income (loss)	1,085	343	(1,135)	701
Interest expense	68	56	130	158
Other income, net
Income before income tax expense	1,017	287	(1,265)	543
Income tax expense	255	14	(191)	(71)
Net income	762	273	(1,074)	614
Depreciation and amortization	358	339	1,079	1,018
Capital expenditures	293	172	1,200	683
International Segment [Member]
Net revenues	35,975	33,690	109,853	91,292
Operating income (loss)	1,239	485	2,952	1,583
Interest expense	265	54	756	(41)
Other income, net	(109)	(78)	(413)	(275)
Income before income tax expense	1,083	509	2,609	1,899
Income tax expense	164	196	526	978
Net income	919	313	2,083	921
Depreciation and amortization	164	148	516	508
Capital expenditures	$ 96	$ 183	$ 140	$ 363