Fair Value Measurements - Reconciliation of Derivative Liability (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Change in value	$ 1,454,831	$ (21,574)
Exchange rights
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Value, Beginning balance	36,752
Change in value	(29,000)
Value, Ending balance	7,752
Warrant
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Value, Beginning balance	1,565,874
Change in value	(1,454,831)
Value, Ending balance	$ 111,043