Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Composition of Financial Instruments (Detail)

v2.4.0.6
Financial Instruments - Composition of Financial Instruments (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 60,084 $ 72,102
Gross Unrealized Gains 9 10
Gross Unrealized Losses (4) (30)
Fair Value 60,089 72,082
Government debt securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 6,000 15,966
Gross Unrealized Gains 3 3
Fair Value 6,003 15,969
Corporate debt securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 49,441 41,764
Gross Unrealized Gains 6 7
Gross Unrealized Losses (4) (30)
Fair Value 49,443 41,741
Money market funds [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 4,643 14,372
Fair Value 4,643 14,372
Cash and cash equivalents [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost (4,643) (14,372)
Fair Value (4,643) (14,372)
Investments [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 55,441 57,730
Gross Unrealized Gains 9 10
Gross Unrealized Losses (4) (30)
Fair Value $ 55,446 $ 57,710