Income Taxes - Current Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current provision:
Federal	$ 0	$ 0	$ 0
State	78	30	21
Foreign	2,225	1,772	2,127
Total current provision	2,303	1,802	2,148
Deferred provision (benefit):
Federal	(86)	35	(73)
State	(4)	2	(3)
Foreign	221	(97)	420
Total deferred provision	131	(60)	344
Total income tax provision	$ 2,434	$ 1,742	$ 2,492