Note 10 - Concentrations (Details Textual) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Sales Revenue, Net [Member] | U.S. Government [Member]
Concentration Risk, Percentage	83.90%	81.60%
Sales Revenue, Net [Member] | Four Government Customers [Member]
Concentration Risk, Percentage	61.40%
Number of Major Customers	4
Sales Revenue, Net [Member] | Three Government Customers [Member]
Concentration Risk, Percentage		58.80%
Number of Major Customers		3
Sales Revenue, Net [Member] | One Commercial Customer [Member]
Concentration Risk, Percentage	14.10%	14.10%
Number of Major Customers	1	1
Accounts Receivable [Member] | Four Government Customers [Member]
Concentration Risk, Percentage	48.90%	65.20%
Number of Major Customers	4	4
Accounts Receivable [Member] | One Commercial Customer [Member]
Concentration Risk, Percentage	10.10%	15.00%
Number of Major Customers	1	1