Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($)	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Intangible Assets Net Excluding Goodwill [Abstract]
Intangible assets subject to amortization, beginning balance	$ 20,464,439
Intangible assets subject to amortization, Amortization	(1,700,429)	$ (1,700,429)	$ (1,714,313)
Intangible assets subject to amortization, ending balance	$ 18,764,010	$ 20,464,439

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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