v2.3.0.15
Stock Based Compensation (Details) (USD $)
Share data in Thousands, except Per Share data, unless otherwise specified
3 Months Ended9 Months Ended
Oct. 30, 2011
Oct. 31, 2010
Oct. 30, 2011
Oct. 31, 2010
Fair value of stock options granted under stock option plans and shares issued under employee stock purchase plan    
Cost of revenue$ 3,049,000$ 2,490,000$ 8,274,000$ 6,582,000
Research and development19,308,00014,104,00059,594,00043,251,000
Sales, general and administrative10,872,0008,585,00033,050,00025,155,000
Stock Options granted (in shares)3,0003,0006,2715,700
Estimated grant-date fair value of stock options21,800,00013,700,00051,400,00033,500,000
Weighted average grant-date fair value per option$ 7.35$ 4.60$ 8.20$ 5.90
Restricted stock units granted (in shares)3,1003,9006,8026,800
Estimated grant-date fair value of RSU's43,900,00040,800,000111,800,00091,900,000
Weighted average grant date fair value of restricted stock units granted$ 14.34$ 10.53$ 16.43$ 13.50
Stock-based compensation expense related to equity awards not expected to vest11,800,000 29,200,000 
Aggregate amount of unearned stock-based compensation expense related to equity awards, adjusted for estimated forfeitures$ 206,100,000$ 164,700,000$ 206,100,000$ 164,700,000
Unearned stock-based compensation expense related to stock options weighted average amortization period (in years)  2.71.8
Unearned stock-based compensation expense related to RSUs weighted average amortization period (in years)  2.72.6
Stock Options    
Stock options beginning balance (in shares)  44,001 
Stock Options granted (in shares)3,0003,0006,2715,700
Stock options exercised (in shares)  (13,714) 
Stock options cancelled (in shares)  (1,514) 
Stock options ending balance (in shares)35,044 35,044 
Weighted average exercise price of stock options at beginning of period  $ 12.88 
Weighted average exercise price of stock options granted$ 16.22 $ 16.22 
Weighted average exercise price of stock options exercised$ 10.69 $ 10.69 
Weighted average exercise price of stock options cancelled  $ 14.61 
Weighted average exercise price of stock options at end of period$ 14.26 $ 14.26 
Restricted Stock Units    
Restricted stock units beginning balance (in shares)  10,612 
Restricted stock units granted (in shares)3,1003,9006,8026,800
Restricted stock units vested (in shares)  (3,441) 
Restricted stock units cancelled (in shares)  (713) 
Restricted stock units ending balance (in shares)13,260 13,260 
Weighted average grant date fair value of restricted stock units at beginning of period  $ 13.23 
Weighted average grant date fair value of restricted stock units granted$ 14.34$ 10.53$ 16.43$ 13.50
Weighted average exercise price of stock options exercised  $ 12.02 
Weighted average grant date fair value of restricted stock units cancelled$ 14.62 $ 14.62 
Weighted average grant date fair value of restricted stock units at end of period$ 15.11 $ 15.11 
Stock Options
    
Fair value of stock options granted under stock option plans and shares issued under employee stock purchase plan    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used(Using a binomial model)(Using a binomial model)(Using a binomial model)(Using a binomial model)
Weighted average expected life of stock options (in years), minimum4.14.03.63.1
Weighted average expected life of stock options (in years), maximum4.95.55.46.7
Risk free interest rate, minimum (in hundredths)1.90%1.90%1.90%1.90%
Risk free interest rate, maximum (in hundredths)2.40%2.70%3.80%3.00%
Volatility rate, minimum (in hundredths)58.00%46.00%46.00%43.00%
Volatility rate, maximum (in hundredths)65.00%47.00%65.00%53.00%
Employee Stock Purchase Plan
    
Fair value of stock options granted under stock option plans and shares issued under employee stock purchase plan    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used(Using a Black-Scholes model)(Using a Black-Scholes model)(Using a Black-Scholes model)(Using a Black-Scholes model)
Weighted average expected life of stock options (in years), minimum0.50.50.50.5
Weighted average expected life of stock options (in years), maximum2.02.02.02.0
Risk free interest rate, minimum (in hundredths)0.10%0.20%0.10%0.20%
Risk free interest rate, maximum (in hundredths)0.20%0.50%0.70%0.80%
Volatility rate, minimum (in hundredths)61.00%47.00%57.00%45.00%
Volatility rate, maximum (in hundredths)  61.00%47.00%