Investments - Summary of Fair Value of Investments Measured on Recurring Basis (Detail) (USD $)	Mar. 31, 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	$ 22,483,002	$ 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	19,965,390	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		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	12,203,241	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	5,853,130	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	1,909,019	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	2,517,612	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	766,410	1,564,505
Long-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	751,462
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
Long-term Investments [Member] | Recurring [Member] | Level-2 [Member] | Corporate debt securities [Member] | Agency [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis, total	$ 999,740