Financial Assets Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term investments Commercial paper	$ 4,601us-gaap_AvailableForSaleSecurities	$ 0us-gaap_AvailableForSaleSecurities
Total assets measured and recorded at fair value	4,601us-gaap_AssetsFairValueDisclosure	168,078us-gaap_AssetsFairValueDisclosure
Foreign exchange forward contracts	1,851us-gaap_DerivativeLiabilities	514us-gaap_DerivativeLiabilities
Contingent consideration obligation	0	1,282
Total liabilities measured and recorded at fair value	1,851us-gaap_LiabilitiesFairValueDisclosure	1,796us-gaap_LiabilitiesFairValueDisclosure
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	49,988
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	118,090
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term investments Commercial paper	4,601	0
Total assets measured and recorded at fair value	4,601	118,090
Foreign exchange forward contracts	0	0
Contingent consideration obligation	0	0
Total liabilities measured and recorded at fair value	0	0
Fair Value, Inputs, Level 1 \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Inputs, Level 1 \| Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	118,090
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term investments Commercial paper	0	0
Total assets measured and recorded at fair value	0	49,988
Foreign exchange forward contracts	1,851	514
Contingent consideration obligation	0	0
Total liabilities measured and recorded at fair value	1,851	514
Fair Value, Inputs, Level 2 \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	49,988
Fair Value, Inputs, Level 2 \| Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Short-term investments Commercial paper	0	0
Total assets measured and recorded at fair value	0	0
Foreign exchange forward contracts	0	0
Contingent consideration obligation	0	1,282
Total liabilities measured and recorded at fair value	0	1,282
Fair Value, Inputs, Level 3 [Member] \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member] \| Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value of financial and nonfinancial obligations.

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