Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments (Details 1)

v2.4.0.6
Financial Instruments (Details 1) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities $ 72,161 $ 72,082
Money market funds [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 378 14,372
Fair Value Measurements Recurring [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 72,161 72,082
Fair Value Measurements Recurring [Member] | Government debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 12,000 15,969
Fair Value Measurements Recurring [Member] | Corporate debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 59,783 41,741
Fair Value Measurements Recurring [Member] | Money market funds [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 378 14,372
Fair Value Measurements Recurring [Member] | Quoted prices In Active Market For Identical Assets (Level 1) [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 378 14,372
Fair Value Measurements Recurring [Member] | Quoted prices In Active Market For Identical Assets (Level 1) [Member] | Government debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities     
Fair Value Measurements Recurring [Member] | Quoted prices In Active Market For Identical Assets (Level 1) [Member] | Corporate debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities     
Fair Value Measurements Recurring [Member] | Quoted prices In Active Market For Identical Assets (Level 1) [Member] | Money market funds [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 378 14,372
Fair Value Measurements Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 71,783 57,710
Fair Value Measurements Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Government debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 12,000 15,969
Fair Value Measurements Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities 59,783 41,741
Fair Value Measurements Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Money market funds [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities     
Fair Value Measurements Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities      
Fair Value Measurements Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Government debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities      
Fair Value Measurements Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate debt securities [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities      
Fair Value Measurements Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Money market funds [Member]
   
Financial instruments measured on recurring basis    
Fair value, available-for-sale securities