Note 7 - Segment, Significant Customers and Geographic Information - Customers with Sales and Accounts Receivable Greater Than 10% (Details) - Customer Concentration Risk [Member]	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue Benchmark [Member]
Concentration risk	75.00%	88.00%	79.00%	83.00%
Revenue Benchmark [Member] | Distributor A [Member]
Concentration risk	22.00%	24.00%	23.00%	23.00%
Revenue Benchmark [Member] | Distributor B [Member]
Concentration risk	11.00%
Revenue Benchmark [Member] | Customer A (Direct) [Member]
Concentration risk	14.00%		11.00%
Accounts Receivable [Member] | Distributor A [Member]
Concentration risk			21.00%		24.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration risk			14.00%		11.00%
Accounts Receivable [Member] | Value Added Reseller A [Member]
Concentration risk			11.00%		13.00%
Accounts Receivable [Member] | Customer A (Direct) [Member]
Concentration risk			26.00%