Accounts Receivable, Net and Revenue Concentrations - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Allowance for Doubtful Accounts
Balance at beginning of period	$ 822	$ 616	$ 478
Additions to costs and expenses	183	299	249
(Write-offs)/Foreign exchange effects	(101)	(93)	(111)
Balance at end of period	$ 904	$ 822	$ 616