Convertible and Long-term Debt Obligations - Schedule of Aggregate Amount of Interest Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Disclosure [Abstract]
Contractual interest coupon	$ 6,615	$ 8,362	$ 23,330	$ 23,410
Amortization of debt issuance costs	4,952	1,945	8,835	5,202
Amortization of debt discount	24,660	24,802	75,493	72,653
Total	$ 36,227	$ 35,109	$ 107,658	$ 101,265