Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Sep. 30, 2017	Jan. 31, 2013	Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration obligations	$ 0		$ 0			$ 0
2012 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants issued to acquire Common Stock								912,543
Warrants cancelled upon expiration					143,811
2013 Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants issued to acquire Common Stock							833,530
Warrants outstanding	0		0
Warrant
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-cash gain (loss) from change in fair value of the derivative liability	$ 0	$ 61,915	$ 432,141	$ 1,490,863