Note 16 - Significant Customers - Customers Concentration Summary (Details) - Customer Concentration Risk [Member]		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Sales Revenue, Net [Member] | Distributor A [Member]
Concentration risk		17.00%		22.00%		24.00%
Sales Revenue, Net [Member] | Distributor B [Member]
Concentration risk	[1]
Sales Revenue, Net [Member] | Distributor C [Member]
Concentration risk		10.00%			[1]		[1]
Sales Revenue, Net [Member] | Value-added Reseller D [Member]
Concentration risk	[1]
Accounts Receivable [Member] | Distributor A [Member]
Concentration risk		16.00%		19.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration risk			[1]	17.00%
Accounts Receivable [Member] | Distributor C [Member]
Concentration risk	[1]
Accounts Receivable [Member] | Value-added Reseller D [Member]
Concentration risk		15.00%			[1]

[1] Represents less than 10%.