Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Additional Information (Detail)

v2.4.0.8
Financial Instruments - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
debt_security
Dec. 31, 2012
Debt Instrument [Line Items]    
Number of corporate debt securities in an unrealized loss position 12  
Fair value of corporate debt in an unrealized loss position $ 19,500,000  
Available-for-sale securities, gross unrealized loss accumulated in investments 9,000 4,000
Transfer of securities, Level 1 0  
Transfer of securities, Level 2 0  
Transfer of securities, Level 3 $ 0  
Minimum [Member]
   
Debt Instrument [Line Items]    
Due date of company's long term available for sale securities 1 year  
Maximum [Member]
   
Debt Instrument [Line Items]    
Period of unrealized loss position 12 months  
Due date of company's long term available for sale securities 2 years