Income Taxes - Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Loss before income taxes	$ (194,151)	$ (86,978)	$ (85,719)
Domestic
Income Tax [Line Items]
Loss before income taxes	(157,067)	(69,287)	(83,256)
Foreign
Income Tax [Line Items]
Loss before income taxes	$ (37,084)	$ (17,691)	$ (2,463)