Income Taxes - Components of Effective Income Tax Reconciliation (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
Effective Income Tax Rate Reconciliation
U.S. Federal tax benefit at statutory rates									$ (22,310)	$ (28,681)	$ (21,795)
State income taxes, net of federal tax benefit									(855)	(1,632)	(2,013)
Foreign rate differential									3,711	3,964	734
Stock based compensation									4,467	4,673	4,121
Other permanent differences									(750)	(99)	941
Other									1,494	536	(82)
Valuation allowance									15,450	22,420	18,949
Total income tax provision (benefit)	$ 313	$ 218	$ 141	$ 535	$ 391	$ 132	$ 380	$ 278	$ 1,207	$ 1,181	$ 855