v2.4.0.6
Common Stock and Stockholders Equity (Deficit) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 9 Months Ended
Oct. 31, 2012
Summary of Stock option activity  
Balance as of January 31, 2012, Shares Available for Grant 5,443,075
Stock option grants, Shares Available for Grant 3
Stock options canceled, Shares Available for Grant 327,725
Balance as of October 31, 2012, Shares Available for Grant 39,201,600
Balance as of January 31, 2012, Outstanding Stock Options 29,211,475
Stock option grants, Outstanding Stock Options 5,329,200
Stock options exercised, Outstanding Stock Options (4,426,380)
Stock options canceled, Outstanding Stock Options (327,725)
Balance as of October 31, 2012, Outstanding Stock Options 29,786,570
Balance as of January 31, 2012, Weighted-Average Exercise Price $ 1.55
Stock option grants, Weighted-Average Exercise Price $ 8.35
Stock options exercised, Weighted-Average Exercise Price $ 2.28
Stock options canceled, Weighted-Average Exercise Price $ 3.85
Balance as of October 31, 2012, Weighted-Average Exercise Price $ 2.64
Balance as of January 31, 2012, Aggregate Intrinsic Value $ 98,241
Balance as of October 31, 2012, Aggregate Intrinsic Value $ 1,366,115
2005 Stock Plan [Member]
  
Summary of Stock option activity  
New shares authorized, Shares Available for Grant 15,000,000
2012 Equity Incentive Plan [Member]
  
Summary of Stock option activity  
New shares authorized, Shares Available for Grant 25,000,000
Restricted Stock [Member]
  
Summary of Stock option activity  
Restricted stock awards granted, Shares Available for Grant (1,240,000)