Fair Value Measurements - Fair Value Measurements for Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Sep. 30, 2016	Sep. 30, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities	$ 1,602,626	$ 1,301,604
Acquisition-related contingent consideration obligations	0	5,862,464
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	85,366,448	81,214,354
Derivative liabilities	1,602,626	1,301,604
Acquisition-related contingent consideration obligations		5,862,464
Fair Value, Measurements, Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	85,366,448	81,214,354
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities	$ 1,602,626	1,301,604
Acquisition-related contingent consideration obligations		$ 5,862,464