|
Fair Value (Details) (USD $)
In Thousands, unless otherwise specified |
Jul. 31, 2012
|
Jan. 31, 2012
|
|---|---|---|
| Fair Value | ||
| Fair value of financial assets and liabilities | $ 69,190 | $ 83,977 |
|
Money market funds
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 31,932 | 31,614 |
|
Commercial paper
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 22,944 | 30,480 |
|
Corporate debt securities
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 11,814 | 20,983 |
|
U.S. agency notes
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 2,500 | 900 |
|
Quoted Prices in Active Markets for Identical Instruments (Level 1)
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 31,932 | 31,614 |
|
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Money market funds
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 31,932 | 31,614 |
|
Significant Other Observable Inputs (Level 2)
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 37,258 | 52,363 |
|
Significant Other Observable Inputs (Level 2) | Commercial paper
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 22,944 | 30,480 |
|
Significant Other Observable Inputs (Level 2) | Corporate debt securities
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 11,814 | 20,983 |
|
Significant Other Observable Inputs (Level 2) | U.S. agency notes
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 2,500 | 900 |
|
Total
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 69,190 | 83,977 |
|
Total | Money market funds
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 31,932 | 31,614 |
|
Total | Commercial paper
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 22,944 | 30,480 |
|
Total | Corporate debt securities
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | 11,814 | 20,983 |
|
Total | U.S. agency notes
|
||
| Fair Value | ||
| Fair value of financial assets and liabilities | $ 2,500 | $ 900 |