Convertible and Long-term Debt Obligations - Schedule of Aggregate Amount of Interest Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Debt Disclosure [Abstract]
Contractual interest coupon	$ 8,324	$ 7,741	$ 16,715	$ 15,048
Amortization of debt issuance costs	1,985	1,727	3,883	3,257
Amortization of debt discount	25,642	24,213	50,833	47,851
Total	$ 35,951	$ 33,681	$ 71,431	$ 66,156