Investments - Summary of Short and Long-term Investments (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Schedule Of Investments [Line Items]
Gross Unrealized Gains	$ 0	$ 7,500
Gross Unrealized Losses	(217,216)	(41,643)
Fair Value	25,533,387	10,698,271
Commercial notes (due within one year), amortized cost	15,912,757	9,030,261
Commercial notes (due after one year through two years, amortized cost	9,837,846	1,702,153
Total	25,750,603	10,732,414
Commercial Notes Due Within One Year
Schedule Of Investments [Line Items]
Gross Unrealized Gains	0	7,500
Gross Unrealized Losses	(103,924)	(39,281)
Fair Value	15,808,833	8,998,480
Commercial Notes Due After One Year Through Two Years
Schedule Of Investments [Line Items]
Gross Unrealized Gains	0
Gross Unrealized Losses	(113,292)	(2,362)
Fair Value	$ 9,724,554	$ 1,699,791