Note 2 - Revenue; Accounts and Unbilled Receivables (Details Textual)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Customer Contracts, Notice of Termination Period (Day)	60 days
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers	4
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Three Customers [Member]
Concentration Risk, Percentage	66.00%	72.00%
Customer Concentration Risk [Member] | Accounts and Unbilled Receivables [Member]
Number of Major Customers	2	4
Customer Concentration Risk [Member] | Accounts and Unbilled Receivables [Member] | Four Non-CSB Customers [Member]
Concentration Risk, Percentage	52.00%	65.00%
Customer Concentration Risk [Member] | Accounts and Unbilled Receivables [Member] | Twelve CSB Customers [Member]
Concentration Risk, Percentage	77.00%	96.00%
Customer Concentration Risk [Member] | Accounts and Unbilled Receivables [Member] | CSB Customers [Member]
Number of Major Customers	11	12