v2.4.0.8
Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Sep. 30, 2013
Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost $ 23,406 $ 41,750 $ 40,202 $ 37,483
Cash and cash equivalents, Gross Unrealized Gains          
Short-term investment, Gross Unrealized Gains 8      
Gross Unrealized Gains 8      
Cash and Cash equivalent, Gross Unrealized Losses          
Short-term investment, Gross Unrealized (Losses) (51) (2)    
Gross Unrealized Losses (51) (2)    
Cash
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Gross Unrealized Gains          
Cash and Cash equivalent, Gross Unrealized Losses          
Term deposits
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Gross Unrealized Gains         
Cash and Cash equivalent, Gross Unrealized Losses         
Money market funds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Gross Unrealized Gains          
Cash and Cash equivalent, Gross Unrealized Losses          
Federal and municipal obligations
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Gross Unrealized Gains         
Cash and Cash equivalent, Gross Unrealized Losses         
Short-term investment, Gross Unrealized (Losses) (18,900) (18,100)    
Corporate bonds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Gross Unrealized Gains 8 [1]      
Short-term investment, Gross Unrealized (Losses) (51) [1] (2) [2]    
Estimated Fair Value
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost 34,930 38,150    
Total 58,336 79,900    
Cash and cash equivalents, Estimated Fair Value 23,406 41,750    
Estimated Fair Value | Cash
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Estimated Fair Value 20,697 25,540    
Estimated Fair Value | Term deposits
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Estimated Fair Value   7,122    
Estimated Fair Value | Money market funds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Estimated Fair Value 2,709 6,088    
Estimated Fair Value | Federal and municipal obligations
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost   1,000    
Cash and cash equivalents, Estimated Fair Value   3,000    
Estimated Fair Value | Commercial paper
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost   4,498 [2]    
Estimated Fair Value | Corporate bonds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost 34,930 [1] 32,652 [2]    
Cost
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost 23,406 41,750    
Short-term investment, Cost 34,973 38,152    
Total 58,379 79,902    
Cost | Cash
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost 20,697 25,540    
Cost | Term deposits
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost   7,122    
Cost | Money market funds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost 2,709 6,088    
Cost | Federal and municipal obligations
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Cash and cash equivalents, Cost   3,000    
Short-term investment, Cost   1,000    
Cost | Commercial paper
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost   4,498 [2]    
Cost | Corporate bonds
        
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Short-term investment, Cost $ 34,973 [1] $ 32,654 [2]    
[1] Securities totaling approximately $18.9 million were in an unrealized loss position at September 30, 2014. None of these securities were in a continuous unrealized loss position for greater than 12 months.
[2] Securities totaling approximately $18.1 million were in an unrealized loss position at December 31, 2013. None of these securities were in a continuous unrealized loss position for greater than 12 months.