Geographical Information (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Geographical Information
Property, Plant and Equipment, Net	$ 40,038	$ 35,909	$ 35,909
United States
Geographical Information
Property, Plant and Equipment, Net	34,687	30,647
India
Geographical Information
Property, Plant and Equipment, Net	4,793	4,907
Other
Geographical Information
Property, Plant and Equipment, Net	$ 558	$ 355