Note 9 - Segment Information - Geographic Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net revenues	$ 66,440	$ 58,388	$ 191,823	$ 172,191
BRAZIL
Net revenues	$ 16,829	$ 12,645
BRAZIL | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 48,974	$ 39,100
Percent of consolidated net revenue	25.30%	21.70%	25.50%	22.70%
SOUTH AFRICA
Net revenues	$ 6,589	$ 6,807
SOUTH AFRICA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 19,565	$ 21,651
Percent of consolidated net revenue	9.90%	11.70%	10.20%	12.60%
MEXICO
Net revenues	$ 5,676	$ 5,142
MEXICO | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 16,627	$ 15,738
Percent of consolidated net revenue	8.50%	8.80%	8.70%	9.10%
CHINA
Net revenues	$ 2,889	$ 3,338
CHINA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 9,348	$ 9,870
Percent of consolidated net revenue	4.30%	5.70%	4.90%	5.70%
INDIA
Net revenues	$ 2,777	$ 3,080
INDIA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 8,372	$ 8,086
Percent of consolidated net revenue	4.20%	5.30%	4.40%	4.70%
CANADA
Net revenues	$ 2,267	$ 2,065
CANADA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 6,538	$ 6,871
Percent of consolidated net revenue	3.40%	3.50%	3.40%	4.00%
JAPAN
Net revenues	$ 2,107	$ 1,947
JAPAN | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 6,670	$ 5,725
Percent of consolidated net revenue	3.20%	3.30%	3.50%	3.30%
AUSTRALIA
Net revenues	$ 759	$ 892
AUSTRALIA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 2,386	$ 2,629
Percent of consolidated net revenue	1.10%	1.50%	1.20%	1.50%
TURKEY
Net revenues	$ 67	$ 60
TURKEY | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 201	$ 183
Percent of consolidated net revenue	0.10%	0.10%	0.10%	0.10%
International [Member]
Net revenues	$ 39,960	$ 35,976
International [Member] | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Net revenues			$ 118,681	$ 109,853
Percent of consolidated net revenue	60.00%	61.60%	61.90%	63.70%