Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020	Jun. 30, 2021 USD ($)	Jun. 30, 2020	Dec. 31, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss, Current	$ 1,476		$ 1,476		$ 2,101
Allowance for Accounts Receivable, Current, Doubtful Accounts	$ 622		$ 622		$ 1,127
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Top Three Customers [Member]
Number of Major Customers	3	3	3	3
Concentration Risk, Percentage	34.00%	25.00%	31.00%	26.00%
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | One of Top Three Customers [Member]
Number of Major Customers	1	1	1	1
Concentration Risk, Percentage	15.00%	5.00%	5.00%	10.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Top Three Customers [Member]
Number of Major Customers			3		3
Concentration Risk, Percentage			43.00%		21.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | One of Top Three Customers [Member]
Number of Major Customers			1		1
Concentration Risk, Percentage			2.00%		10.00%