v2.4.0.8
Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value $ 37,639 $ 54,360
Money market funds
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 2,709 [1] 6,088 [1]
Term deposits
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   7,122 [1]
Commercial paper
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   4,498 [2]
Corporate bonds
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 34,930 [2] 32,652 [2]
Federal and municipal obligations
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   4,000 [3]
Quoted Prices In Active Markets for Identical Assets (Level 1)
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 2,709 13,210
Quoted Prices In Active Markets for Identical Assets (Level 1) | Money market funds
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 2,709 [1] 6,088 [1]
Quoted Prices In Active Markets for Identical Assets (Level 1) | Term deposits
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   7,122 [1]
Significant Other Observable Inputs (Level 2)
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 34,390 41,150
Significant Other Observable Inputs (Level 2) | Commercial paper
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   4,498 [2]
Significant Other Observable Inputs (Level 2) | Corporate bonds
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value 34,930 [2] 32,652 [2]
Significant Other Observable Inputs (Level 2) | Federal and municipal obligations
    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Total, Estimated Fair Value   $ 4,000 [3]
[1] Included in cash and cash equivalents in the Company's Condensed Consolidated Balance Sheet.
[2] Included in short-term investments in the Company's Condensed Consolidated Balance Sheet
[3] Of this amount, approximately $3 million was included in cash equivalents at December 31, 2013 and the remainder was included in short-term investments in the Company's Condensed Consolidated Balance Sheet.