Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1,700,429	$ 1,700,429	$ 1,714,313
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 in 2022	1,700,429
Amortization of license agreements in 2023	1,700,429
Amortization of license agreements, thereafter	$ 10,261,865
Novartis | Licensing Agreement
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets	21 years
Finite-lived intangible assets, accumulated amortization	$ 531,786
Novartis | Patents
Finite Lived Intangible Assets [Line Items]
Amortization period of intangible assets	14 years
Finite-lived intangible assets, accumulated amortization	$ 5,561,419