Note 16 - Significant Customers - Customers Concentration Summary (Details) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Sales Revenue, Net [Member] | Distributor A [Member]
Concentration risk	22.00%	17.00%	22.00%
Sales Revenue, Net [Member] | Distributor B [Member]
Concentration risk	10.00%
Sales Revenue, Net [Member] | Distributor C [Member]
Concentration risk		10.00%
Accounts Receivable [Member] | Distributor A [Member]
Concentration risk	25.00%	16.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration risk	16.00%
Accounts Receivable [Member] | Value-added Reseller D [Member]
Concentration risk		15.00%