Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1,046,571	$ 54,653	$ 236,009
Amortization of license agreements in 2016	1,714,313
Amortization of license agreements in 2017	1,700,429
Amortization of license agreements in 2018	1,700,429
Amortization of license agreements in 2019	1,700,429
Amortization of license agreements in 2020	1,700,429
Amortization of license agreements in 2021	1,700,429
Amortization of license agreements, thereafter	$ 13,662,723
Novartis | Licensing Agreements
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets	21 years
Finite-lived intangible assets, accumulated amortization	$ 86,570
Novartis | Patents
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets	14 years
Finite-lived intangible assets, accumulated amortization	$ 905,347
Roche RNAi | Licensing Agreements
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets	4 years
Finite-lived intangible assets, accumulated amortization	$ 216,116