Note 7 - Concentration or Revenue - Concentration of Revenue (Details) - Customer Concentration Risk [Member] - Sales Revenue, Net [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Customer A [Member]
Concentration risk	10.50%	25.60%	15.20%	24.40%
Customer B [Member]
Concentration risk	8.00%	20.90%	10.40%	19.70%
Customer C [Member]
Concentration risk	5.80%	10.10%	7.80%	9.20%
Customer D [Member]
Concentration risk	43.40%	0.00%	27.80%	0.60%