Warrant Liability - Summary of Changes in Fair Value of Warrant Liability (Detail) - Jun. 30, 2015 - Series A Warrants [Member] - USD ($)	Total
Class of Warrant or Right [Line Items]
Number of Warrants, beginning balance	6,936,880
Number of Warrants, changes in fair value	0
Number of Warrants, ending balance	6,936,880
Fair value of warrant liability, beginning balance	$ 1,684,551
Fair value, changes in fair value at period end	(641,037)
Fair value of warrant liability, ending balance	$ 1,043,514