Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal									$ 0	$ 0	$ 0
State									70	1	0
Foreign									2,920	2,230	2,103
Current provision for income taxes									2,990	2,231	2,103
Deferred:
Federal									(145)	(155)	0
State									0	0	0
Foreign									(1,524)	886	(861)
Deferred provision for income taxes									(1,669)	731	(861)
Total	$ (252)	$ 597	$ 189	$ 787	$ 526	$ 930	$ 879	$ 627	$ 1,321	$ 2,962	$ 1,242