XML 21 R34.htm IDEA: XBRL DOCUMENT v2.4.0.8
Fair Value-Based Measurements and Weighted-Average Assumptions (Detail) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Stock Options
       
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Weighted-average fair value $ 1.15 $ 3.34 $ 2.43 $ 3.30
Risk-free interest rate 1.90% 0.60% 1.10% 0.50%
Expected life (in years) 5 years 7 months 6 days 4 years 5 years 10 months 24 days 4 years
Volatility 1.50% 1.60% 1.40% 1.60%
Employee Stock Purchase Plan
       
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Weighted-average fair value     $ 0.93 $ 3.80
Risk-free interest rate     0.20% 0.20%
Expected life (in years)     1 year 3 months 18 days 1 year
Volatility     0.80% 1.60%