Derivative Financial Instruments - Components of (Expense) Income of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative (loss) gain	$ (13,167)	$ 121
Free Standing Warrants Assets, Related Party [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative (loss) gain		$ (51)
Shares into which derivative liability can be settled		1,999,436
Free Standing Warrants Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative (loss) gain	$ (13,167)	$ 172