Stock-Based Compensation - Summarize Information about Stock Options (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Jun. 30, 2015	Sep. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, beginning balance	3,850,840	3,419,285
Number of Options Outstanding, Granted	1,670,000	1,039,000
Number of Options Outstanding, Cancelled	(95,948)	(152,582)
Number of Options Outstanding, Exercised	(17,500)	(454,863)
Number of Options Outstanding, ending balance	5,407,392	3,850,840
Number of Options Outstanding, Exercisable	2,416,134
Weighted Average Exercise Price Per Share, beginning balance	$ 6.99	$ 4.68
Weighted Average Exercise Price Per Share, Granted	6.36	14.05
Weighted Average Exercise Price Per Share, Cancelled	12.03	6.05
Weighted Average Exercise Price Per Share, Exercised	2.46	6.00
Weighted Average Exercise Price Per Share, ending balance	6.72	$ 6.99
Weighted Average Exercise Price Per Share, Exercisable	$ 6.03
Weighted Average Remaining Contractual Term	8 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 1 month 6 days
Aggregate Intrinsic Value	$ 10,487,890
Aggregate Intrinsic Value, Exercisable	$ 5,894,091