Investments - Summary of Short and Long-term Investments (Detail) (USD $)	Jun. 30, 2014	Sep. 30, 2013
Schedule Of Investments [Line Items]
Gross Unrealized Gains	$ 5,749	$ 7,500
Gross Unrealized Losses	(389,403)	(41,643)
Fair Value	49,735,616	10,698,271
Commercial notes (due within one year), Amortized Cost	23,834,408	9,030,261
Commercial notes (due after one year within three years), Amortized Cost	26,284,862	1,702,153
Total	50,119,270	10,732,414
Commercial Notes Due Within One Year
Schedule Of Investments [Line Items]
Gross Unrealized Gains	1,850	7,500
Gross Unrealized Losses	(237,181)	(39,281)
Fair Value	23,599,077	8,998,480
Commercial Notes Due After One Year Within Three Years
Schedule Of Investments [Line Items]
Gross Unrealized Gains	3,899
Gross Unrealized Losses	(152,222)	(2,362)
Fair Value	$ 26,136,599	$ 1,699,791