Note 2 - Summary of Significant Accounting Policies - Revenues and Accounts Receivable From Major Distribution Partners and Customers (Details) - Customer Concentration Risk [Member]	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Sales Revenue, Net [Member] | Distributor A [Member]
Concentration risk percentage	25.00%	21.00%	24.00%	18.00%
Sales Revenue, Net [Member] | Distributor B [Member]
Concentration risk percentage	24.00%	21.00%	24.00%	19.00%
Sales Revenue, Net [Member] | Distributor C [Member]
Concentration risk percentage	23.00%	16.00%	21.00%	15.00%
Accounts Receivable [Member] | Distributor A [Member]
Concentration risk percentage			30.00%		22.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration risk percentage			22.00%		24.00%
Accounts Receivable [Member] | Distributor C [Member]
Concentration risk percentage			31.00%		31.00%