Summary of Significant Accounting Policies - Summarized Financial Data of Equity Method Investments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Operating expenses									$ 320,469	$ 141,892	$ 81,783
Operating loss	$ (34,395)	$ (7,916)	$ (17,430)	$ (87,123)	$ (18,961)	$ (15,047)	$ (18,082)	$ (17,872)	(146,864)	(69,962)	(58,023)
Other									68,830	(10,497)	17,721
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Current assets	28,123				63,627				28,123	63,627
Non-current assets	1,539				1,259				1,539	1,259
Total assets	29,662				64,886				29,662	64,886
Current liabilities	6,274				15,346				6,274	15,346
Non-current liabilities	0				570				0	570
Total liabilities	6,274				15,916				6,274	15,916
Net assets	$ 23,388				$ 48,970				23,388	48,970
Revenues, net									1,720	2,313	1,832
Operating expenses									123,842	62,161	77,011
Operating loss									(122,122)	(59,848)	(75,179)
Other									(54)	11,753	743
Net loss									$ (122,176)	$ (48,095)	$ (74,436)