Net Income (Loss) Per Share - Reconciliation of Numerator and Denominator of Basic and Diluted Net Income (Loss) Per Share (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Numerator    
Net income (loss) $ 21,198 $ (3,991)
Denominator    
Weighted average shares outstanding, basic 134,777 136,795
Effect of dilutive potential common shares 4,456  
Weighted average shares outstanding, diluted 139,233 136,795
Basic net income (loss) per share $ 0.16 $ (0.03)
Diluted net income (loss) per share $ 0.15 $ (0.03)
Antidilutive employee stock-based awards, excluded 3,870 5,855