Stock-Based Compensation - Summarize Information about Stock Options (Detail) (USD $)	6 Months Ended	12 Months Ended
Mar. 31, 2013	Sep. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, beginning balance	1,910,794	729,096
Number of Options Outstanding, Granted	79,000	1,229,500
Number of Options Outstanding, Cancelled	0	(42,919)
Number of Options Outstanding, Exercised	0	(4,883)
Number of Options Outstanding, ending balance	1,989,794	1,910,794
Weighted-Average Exercise Price Per Share, beginning balance	$ 6.01	$ 9.03
Number of Options Outstanding, Exercisable	1,037,989
Weighted-Average Exercise Price Per Share, Granted	$ 2.20	$ 4.40
Weighted-Average Exercise Price Per Share, Cancelled	$ 0.0	$ 11.77
Weighted-Average Exercise Price Per Share, Exercised	$ 0.00	$ 5.20
Weighted-Average Exercise Price Per Share, ending balance	$ 5.86	$ 6.01
Weighted-Average Exercise Price Per Share, Exercisable	$ 7.24
Weighted-Average Remaining Contractual Term	7 years 9 months 18 days
Weighted-Average Remaining Contractual Term, Exercisable	6 years 8 months 12 days
Aggregate Intrinsic Value	$ 800
Aggregate Intrinsic Value, Exercisable

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Gross number of share options (or share units) granted during the period.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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