Note 8 - Concentrations (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018
Number of Areas in Which Operations are Concentrated			1
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | U.S. Government [Member]
Concentration Risk, Percentage	84.50%	90.60%
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Four Government Customers [Member]
Concentration Risk, Percentage	66.40%
Number of Major Customers	4
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Six Government Customers [Member]
Concentration Risk, Percentage	90.60%
Number of Major Customers	6
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | One Commercial Customer [Member]
Concentration Risk, Percentage	14.50%	6.20%
Number of Major Customers	1	1