Receivables and Prepaid Expenses - Schedule of Receivables and Prepaid Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables And Prepaid Expenses [Abstract]
Advances to and receivables from suppliers	$ 2,924	$ 5,829
Government authorities	2,006	1,867
Prepaid expenses	2,890	2,238
Others	285	150
Receivables and prepaid expenses	$ 8,105	$ 10,084