Cash Equivalents and Investments - Additional Information (Detail) (USD $)
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12 Months Ended | |
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Dec. 31, 2014
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Dec. 31, 2013
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Cash and Cash Equivalents [Line Items] | ||
Investments in continuous unrealized loss position for 12 months or longer | $ 0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss | |
U.S. Treasury Securities [Member] | ||
Cash and Cash Equivalents [Line Items] | ||
U.S. Treasury securities maturity start date | Jan. 01, 2015 | |
U.S. Treasury securities maturity end date | Feb. 27, 2015 | |
Short-term Investments [Member] | ||
Cash and Cash Equivalents [Line Items] | ||
Unrealized Gain (loss) | $ (7,000)us-gaap_UnrealizedGainLossOnInvestments / us-gaap_InvestmentTypeAxis = us-gaap_ShortTermInvestmentsMember |
$ (1,000)us-gaap_UnrealizedGainLossOnInvestments / us-gaap_InvestmentTypeAxis = us-gaap_ShortTermInvestmentsMember |
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- Definition
The latest maturity date when short-term debt instruments are reported on the Schedule of Investments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The earliest maturity date when short-term debt instruments are reported on the Schedule of Investments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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