Note 20 - Concentration of Credit Risk and Major Customers (Details Textual)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Geographic Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Concentration Risk, Percentage	65.00%	65.00%	71.00%
Exporters Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Percentage	35.00%	35.00%	29.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers	3	3	3
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Three Customers [Member]
Concentration Risk, Percentage	55.00%	70.00%	57.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers	3	2