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		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue Benchmark [Member]
Concentration risk	89.00%	80.00%
Revenue Benchmark [Member] | Distributor A [Member]
Concentration risk	26.00%	23.00%
Revenue Benchmark [Member] | Distributor B [Member]
Concentration risk	16.00%
Revenue Benchmark [Member] | Customer A (Direct) [Member]
Concentration risk		10.00%
Accounts Receivable [Member] | Distributor A [Member]
Concentration risk	25.00%		24.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration risk	18.00%		21.00%
Accounts Receivable [Member] | Value Added Reseller A [Member]
Concentration risk	11.00%		13.00%
Accounts Receivable [Member] | Customer A (Direct) [Member]
Concentration risk			10.00%