v2.4.0.8
Assumptions Used to Estimate Fair Value of Stock Options Granted and Stock Purchase Rights Granted Under our Employee Stock Purchase Plan (Detail)
9 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Options
   
Expected volatility, minimum 42.39% 50.03%
Expected volatility, maximum 49.94% 53.58%
Risk-free interest rate, minimum 1.62% 0.77%
Risk-free interest rate, maximum 1.78% 1.40%
Expected dividend yield 0.00% 0.00%
Options | Minimum
   
Expected term (years) 5 years 6 months 11 days 5 years 7 months 10 days
Options | Maximum
   
Expected term (years) 5 years 6 months 26 days 5 years 8 months 1 day
Employee Stock
   
Expected volatility, minimum 21.40% 28.63%
Expected volatility, maximum 62.24% 41.52%
Expected term (years) 1 year 3 months 1 year 3 months
Risk-free interest rate, minimum 0.05% 0.08%
Risk-free interest rate, maximum 0.47% 0.35%
Expected dividend yield 0.00% 0.00%