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Investments and Fair Value Measurement - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2013 | Sep. 30, 2013 | Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items] |  |  |
Investments maturity period | 1 year | 1 year |
Gross Unrealized (Losses) |  |  |
Available-for-sale securities [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Gross Unrealized (Losses) |  |  |
Realized losses | 0 | 0 |
Other-than-temporary impairments of available-for-sale securities | $ 0 | $ 0 | $ 0

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- Definition Investments maturity dates available for sale securities. + References No definition available. + Details
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- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
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- Definition The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
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- Details
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