Accounts Receivable, Net and Revenue Concentrations - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Schedule of Allowance for Doubtful Accounts
Balance at beginning of period	$ 904	$ 822
Additions (reductions) to costs and expenses	167	123
(Write-offs)/Foreign exchange effects	(19)	15
Balance at end of period	$ 1,052	$ 960