Geographic Information (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Revenue earned
Revenue earned from grant	$ 944	$ 1,159
North Carolina State University
Revenue earned
Revenue earned from grant	30
U.S. Department of Energy
Revenue earned
Revenue earned from grant	$ 913
Revenues | North Carolina State University
Revenue earned
Percentage of total revenue	3.00%
Revenues | U.S. Department of Energy
Revenue earned
Percentage of total revenue	97.00%
Sales | North Carolina State University
Revenue earned
Revenue earned from grant		$ 246
Percentage of total revenue		21.22519%
Sales | U.S. Department of Energy
Revenue earned
Revenue earned from grant		$ 913
Percentage of total revenue		78.77481%