Derivative Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring [Member], USD $)	Jun. 30, 2014	Dec. 31, 2013
Fair Value Asset Measured On Recurring Basis [Line Items]
Derivative liabilities- free standing warrants	$ 10,761,692	$ 4,315,183
Level 1 [Member]
Fair Value Asset Measured On Recurring Basis [Line Items]
Derivative liabilities- free standing warrants	0
Level 2 [Member]
Fair Value Asset Measured On Recurring Basis [Line Items]
Derivative liabilities- free standing warrants	10,761,692	4,315,183
Level 3 [Member]
Fair Value Asset Measured On Recurring Basis [Line Items]
Derivative liabilities- free standing warrants	$ 0