Note 5 - Accounts Receivable and Customer Concentrations - Concentration of Revenue (Details) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Customer A [Member] | Sales Revenue, Net [Member]
Concentration risk	13.20%	22.50%
Customer A [Member] | Accounts Receivable [Member]
Concentration risk	14.20%	23.60%
Customer B [Member] | Sales Revenue, Net [Member]
Concentration risk	28.50%	2.00%
Customer B [Member] | Accounts Receivable [Member]
Concentration risk	52.20%	28.90%
Customer C [Member] | Sales Revenue, Net [Member]
Concentration risk	10.30%	18.70%
Customer C [Member] | Accounts Receivable [Member]
Concentration risk	5.20%	6.40%
Customer D [Member] | Sales Revenue, Net [Member]
Concentration risk	3.60%	3.90%
Customer D [Member] | Accounts Receivable [Member]
Concentration risk	3.20%	11.60%