Investments - Summary of Fair Value of Investments Measured on Recurring Basis (Detail) - USD ($)	Jun. 30, 2015	Sep. 30, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	$ 21,985,674	$ 18,341,188
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	21,222,669	16,269,170
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Commercial paper [Member] | Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	1,399,911
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Commercial paper [Member] | Industrial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	749,322	2,198,043
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	10,232,435	9,334,140
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Industrial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	6,328,166	3,980,772
Short-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Utility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	2,512,835	756,215
Long-term Investments [Member] | Recurring [Member] | Level-2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	763,005	2,072,018
Long-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Financial [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	$ 763,005	1,564,505
Long-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Utility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total		$ 507,513