Short-Term Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2012
Schedule Of Short Term Investments And Available For Sale Securities [Line Items]
Accumulated other comprehensive loss	$ 13	$ 30

Accumulated appreciation or loss, net of tax, in value of the total of available-for-sale securities at the end of an accounting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 130

-Paragraph 26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

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-Subparagraph (e)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=20435746&loc=d3e637-108580

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-Publisher FASB

-Name Accounting Standards Codification

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