Note 7 - Concentration of Revenue (Details) - Customer Concentration Risk [Member] - Sales Revenue, Net [Member]	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Customer A [Member]
Concentration risk	14.70%	24.90%	19.00%	23.70%
Customer B [Member]
Concentration risk	15.50%	15.40%	12.40%	19.00%
Customer C [Member]
Concentration risk	10.60%	8.30%	9.50%	8.60%
Customer D [Member]
Concentration risk	14.90%		14.80%