Fair Value of Financial Assets and Liabilities - Summary of Fair Value of Derivative Liabilities on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value Liabilities Measured On Recurring and Nonrecurring Basis [Line Items]
Beginning balance		$ 9,640	$ 62,362
Fair value derivative adjustment	36,305	(9,640)	(58,740)
Allocation of Class A Preferred Stock upon issuance			6,018
Ending balance			9,640
Class A Preferred Stock [Member]
Fair Value Liabilities Measured On Recurring and Nonrecurring Basis [Line Items]
Beginning balance		9,640	29,272
Fair value derivative adjustment		(9,640)	(25,650)
Allocation of Class A Preferred Stock upon issuance			6,018
Ending balance			9,640
Junior Convertible Preferred Stock [Member]
Fair Value Liabilities Measured On Recurring and Nonrecurring Basis [Line Items]
Beginning balance			33,090
Fair value derivative adjustment			(33,090)
Allocation of Class A Preferred Stock upon issuance
Ending balance