Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014	Jun. 30, 2010	Dec. 31, 2012	Jan. 31, 2013
Fair Value Measurements Disclosure [Line Items]
Short term investments	$ 19,561,172		$ 19,561,172		$ 21,653,032
Investments	12,361,068		12,361,068		23,088,346
Total investments	31,922,240		31,922,240		44,741,378
Fair value of investment	31,510,086		31,510,086		44,333,855
Warrants outstanding	1,437,011		1,437,011
Non-cash gain (loss) from change in fair value of the derivative liability	191,910	(2,910,116)	2,371,561	(6,417,612)
Duration of exchange rights			7 years
2010 Warrants
Fair Value Measurements Disclosure [Line Items]
Warrants issued to acquire Common Stock						329,649
Warrants outstanding	24,324		24,324
2012 Warrants
Fair Value Measurements Disclosure [Line Items]
Warrants issued to acquire Common Stock							912,543
Warrants outstanding	265,161		265,161
2013 Warrants
Fair Value Measurements Disclosure [Line Items]
Warrants issued to acquire Common Stock								833,530
Warrants outstanding	12,123		12,123
Ablaris Therapeutics
Fair Value Measurements Disclosure [Line Items]
Warrants outstanding	500,000		500,000
Non-cash gain (loss) from change in fair value of the derivative liability	$ (22,936)	$ (41,109)	$ 179,555	$ (53,191)
Exchange right convertible conversion ratio for first year			0.06
Exchange right convertible conversion ratio for second year			0.04
Exchange right convertible conversion ratio for third year			0.03
Exchange right convertible conversion ratio for fourth year			0.02
Exchange right convertible conversion ratio for fifth year and beyond			0.01
Number of exchange right sold			675,000