Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
VAT receivable	$ 7,640	$ 7,854
Prepaid income tax asset	4,920	5,090
Prepaid and other current assets	1,387	2,664
Total other current assets	$ 13,947	$ 15,608