Investments - Summary of Short and Long-term Investments (Detail) - USD ($)	Mar. 31, 2016	Sep. 30, 2015
Schedule Of Held To Maturity Securities [Line Items]
Commercial notes (due within one year), amortized cost	$ 11,160,442	$ 17,539,902
Total	11,160,442	17,539,902
Gross Unrealized Losses	(122,512)	(304,942)
Fair Value	11,037,930	17,234,960
Commercial Notes Due Within One Year
Schedule Of Held To Maturity Securities [Line Items]
Gross Unrealized Losses	(122,512)	(304,942)
Fair Value	$ 11,037,930	$ 17,234,960

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26626-111562

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