Concentrations (Details)	12 Months Ended
	Dec. 31, 2014 item	Dec. 31, 2013 item
Concentrations
Number of areas in which operations are concentrated	1
One individual commercial customer
Concentrations
Number of customers	1	1
Four government customers
Concentrations
Number of customers	4	4
Total revenues | Customer | U.S. Government
Concentrations
Percentage of revenue	51.40%	50.10%
Total revenues | Customer | One individual commercial customer
Concentrations
Percentage of revenue	30.00%	30.00%
Total revenues | Customer | Four government customers
Concentrations
Percentage of revenue		46.00%