Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) | Mar. 31, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | $131,035 | $8,837 |
Foreign currency derivatives | 1,140 | 873 |
Total investments | 123,552 | 9,820 |
Assets, Total | 392,445 | 85,602 |
Foreign currency derivatives | 1,260 | 1,555 |
Contingent consideration | 258 | 310 |
Liabilities, Total | 1,518 | 1,865 |
Amounts classified as cash equivalents [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Cash and cash equivalents | 136,718 | 66,072 |
Commercial paper [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 73,985 | 5,448 |
Corporate debt securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 28,290 | 1,881 |
Total investments | 42,542 | 1,975 |
Government agency securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 15,802 | 1,508 |
Total investments | 26,091 | 3,405 |
United States government securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | 20,648 | 2,149 |
Other securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 12,958 | ' |
Other securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | 34,271 | 2,291 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Foreign currency derivatives | ' | ' |
Total investments | ' | ' |
Assets, Total | 72,127 | 64,772 |
Foreign currency derivatives | ' | ' |
Contingent consideration | ' | ' |
Liabilities, Total | ' | ' |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 131,035 | 8,837 |
Foreign currency derivatives | 1,140 | 873 |
Total investments | 123,552 | 9,820 |
Assets, Total | 320,318 | 20,830 |
Foreign currency derivatives | 1,260 | 1,555 |
Contingent consideration | ' | ' |
Liabilities, Total | 1,260 | 1,555 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Foreign currency derivatives | ' | ' |
Total investments | ' | ' |
Assets, Total | ' | ' |
Foreign currency derivatives | ' | ' |
Contingent consideration | 258 | 310 |
Liabilities, Total | 258 | 310 |
Fair Value, Measurements, Recurring [Member] | Amounts classified as cash equivalents [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Cash and cash equivalents | 72,127 | 64,772 |
Fair Value, Measurements, Recurring [Member] | Amounts classified as cash equivalents [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Cash and cash equivalents | 64,591 | 1,300 |
Fair Value, Measurements, Recurring [Member] | Amounts classified as cash equivalents [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Cash and cash equivalents | ' | ' |
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 73,985 | 5,448 |
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 28,290 | 1,881 |
Total investments | 42,542 | 1,975 |
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Government agency securities [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Government agency securities [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 15,802 | 1,508 |
Total investments | 26,091 | 3,405 |
Fair Value, Measurements, Recurring [Member] | Government agency securities [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | United States government securities [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | United States government securities [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | 20,648 | 2,149 |
Fair Value, Measurements, Recurring [Member] | United States government securities [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | 12,958 | ' |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total short-term investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | ' | ' |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | 34,271 | 2,291 |
Fair Value, Measurements, Recurring [Member] | Other securities [Member] | Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Total investments | ' | ' |