Note 9 - Segment Information - Geographic Data (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net revenues	$ 68,223	$ 59,224	$ 125,383	$ 113,803
BRAZIL
Net revenues	$ 16,612	$ 13,046
BRAZIL | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 32,145	$ 26,456
Percent of consolidated net revenue	24.30%	22.10%	25.60%	23.30%
SOUTH AFRICA
Net revenues	$ 6,442	$ 7,400
SOUTH AFRICA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 12,976	$ 14,844
Percent of consolidated net revenue	9.40%	12.50%	10.30%	13.10%
MEXICO
Net revenues	$ 5,664	$ 5,236
MEXICO | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 10,951	$ 10,596
Percent of consolidated net revenue	8.30%	8.90%	8.70%	9.30%
CHINA
Net revenues	$ 3,180	$ 4,090
CHINA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 6,459	$ 6,532
Percent of consolidated net revenue	4.70%	6.90%	5.20%	5.80%
INDIA
Net revenues	$ 2,865	$ 2,759
INDIA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 5,595	$ 5,006
Percent of consolidated net revenue	4.20%	4.70%	4.50%	4.40%
CANADA
Net revenues	$ 2,459	$ 1,844
CANADA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 4,563	$ 3,778
Percent of consolidated net revenue	3.60%	3.10%	3.60%	3.30%
JAPAN
Net revenues	$ 2,065	$ 2,382
JAPAN | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 4,271	$ 4,806
Percent of consolidated net revenue	3.00%	4.00%	3.40%	4.20%
AUSTRALIA
Net revenues	$ 863	$ 851
AUSTRALIA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 1,627	$ 1,737
Percent of consolidated net revenue	1.30%	1.40%	1.30%	1.50%
TURKEY
Net revenues	$ 67	$ 60
TURKEY | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 134	$ 123
Percent of consolidated net revenue	0.10%	0.10%	0.10%	0.10%
International [Member]
Net revenues	$ 40,217	$ 37,668
International [Member] | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 78,721	$ 73,878
Percent of consolidated net revenue	58.90%	63.70%	62.70%	65.00%