Stock-Based Compensation - Summarize Information about Stock Options (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options Outstanding, beginning balance	3,419,285	1,910,794	729,096
Number of Options Outstanding, Granted	105,000	1,509,166	1,229,500
Number of Options Outstanding, Cancelled	(37,970)		(42,919)
Number of Options Outstanding, Exercised	(62,825)	(675)	(4,883)
Number of Options Outstanding, ending balance	3,423,490	3,419,285	1,910,794
Number of Options Outstanding, Exercisable	1,377,779
Weighted Average Exercise Price Per Share, beginning balance	$ 4.68	$ 6.10	$ 9.03
Weighted Average Exercise Price Per Share, Granted	$ 7.98	$ 2.03	$ 4.40
Weighted Average Exercise Price Per Share, Cancelled	$ 4.77		$ 11.77
Weighted Average Exercise Price Per Share, Exercised	$ 4.83	$ 3.93	$ 5.20
Weighted Average Exercise Price Per Share, ending balance	$ 4.77	$ 4.68	$ 6.10
Weighted Average Exercise Price Per Share, Exercisable	$ 7.25
Weighted Average Remaining Contractual Term	8 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 7 months 6 days
Aggregate Intrinsic Value	$ 21,646,786
Aggregate Intrinsic Value, Exercisable	$ 7,038,191