Geographical Information (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Geographical Information
Property, Plant and Equipment, Net	$ 40,397	$ 35,909
United States
Geographical Information
Property, Plant and Equipment, Net	35,812	30,647
India
Geographical Information
Property, Plant and Equipment, Net	4,109	4,907
Other
Geographical Information
Property, Plant and Equipment, Net	$ 476	$ 355