Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax provision:
Federal									$ 0	$ 0	$ 0
State									105	147	40
Foreign									1,838	1,139	822
Total current income tax provision									1,943	1,286	862
Deferred income tax benefit:
Federal									0	0	0
State									0	0	0
Foreign									(736)	(105)	(7)
Total deferred income tax benefit									(736)	(105)	(7)
Total income tax provision (benefit)	$ 313	$ 218	$ 141	$ 535	$ 391	$ 132	$ 380	$ 278	$ 1,207	$ 1,181	$ 855