Income Taxes - Reconciliation of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Loss before income taxes	$ (107,147)	$ (80,300)	$ (77,017)
Statutory tax rate	35.00%	35.00%	35.00%
Notional U.S. federal income taxes at statutory rate	$ (37,501)	$ (28,105)	$ (26,956)
Non-deductible expenses	2,621	1,242	1,411
Foreign tax rate differential	18,573	20,261	20,965
Change in valuation allowance	19,550	7,226	4,727
Unrecognized tax expense (benefit)	1,257	(242)	206
Other	(66)
Income tax expenses	$ 4,434	$ 382	$ 353
Effective tax rate	(4.14%)	(0.48%)	(0.46%)