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Common Stock (Details) (USD $)
|
9 Months Ended | 12 Months Ended |
|---|---|---|
|
Oct. 31, 2012
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Jan. 31, 2012
|
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| Common Stock | ||
| Number of shares of common stock authorized | 1,000,000,000 | 106,511,960 |
| Common stock, par value per share (in dollars per share) | $ 0.001 | $ 0.001 |
| Shares of common stock issued | 96,925,524 | 23,092,407 |
| Common stock, shares issued and outstanding | 96,925,524 | 23,092,407 |
| Early Exercise of Employee Options | ||
| Shares of restricted common stock, subject to a repurchase right | 103,240 | 411,318 |
| Portion of shares from early exercises of employee options for which the repurchase right lapses on the first anniversary of the vesting start date. | 0.25 | 0.25 |
| Portion of shares from early exercises of employee options for which the repurchase right lapses on monthly basis after the first anniversary of the vesting start date. | 0.02 | 0.02 |