Note 2 - Summary of Significant Accounting Policies - Concentrations (Details) - customer	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue Benchmark
Concentrations
Number of Major Customers		3
Customer Concentration Risk | Revenue Benchmark
Concentrations
Number of Major Customers	3	3
Customer Concentration Risk | Revenue Benchmark | Customer A
Concentrations
Concentration Risk, Percentage	51.00%
Customer Concentration Risk | Revenue Benchmark | Customer B
Concentrations
Concentration Risk, Percentage		71.00%
Customer Concentration Risk | Revenue Benchmark | Customer C
Concentrations
Concentration Risk, Percentage			74.00%
Customer Concentration Risk | Revenue Benchmark | Total Customer Base
Concentrations
Concentration Risk, Percentage	58.00%	70.00%	53.00%
Customer Concentration Risk | Accounts Receivable. | Total Customer Base
Concentrations
Concentration Risk, Percentage	58.00%	46.00%