Accounts Receivable, Net and Revenue Concentrations - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Schedule of Allowance for Doubtful Accounts
Balance at beginning of period	$ 904	$ 822
Additions (reductions) to costs and expenses	81	116
(Write-offs)/Foreign exchange effects	(35)	4
Balance at end of period	$ 950	$ 942