|
Composition of Certain Financial Statement Captions (Details 2) (USD $)
In Thousands, unless otherwise specified |
Jul. 31, 2012
item
|
Jan. 31, 2012
|
|---|---|---|
| Available-for-sale securities | ||
| Adjusted Cost | $ 69,192 | $ 83,982 |
| Unrealized Gains | 1 | 1 |
| Unrealized Losses | (3) | (6) |
| Fair Value | 69,190 | 83,977 |
| Number of owned securities that were in an unrealized loss position | 16 | |
|
Money market funds
|
||
| Available-for-sale securities | ||
| Adjusted Cost | 31,932 | 31,614 |
| Fair Value | 31,932 | 31,614 |
|
Commercial paper
|
||
| Available-for-sale securities | ||
| Adjusted Cost | 22,944 | 30,481 |
| Unrealized Losses | (1) | |
| Fair Value | 22,944 | 30,480 |
|
Corporate debt securities
|
||
| Available-for-sale securities | ||
| Adjusted Cost | 11,816 | 20,987 |
| Unrealized Gains | 1 | 1 |
| Unrealized Losses | (3) | (5) |
| Fair Value | 11,814 | 20,983 |
|
U.S. agency notes
|
||
| Available-for-sale securities | ||
| Adjusted Cost | 2,500 | 900 |
| Fair Value | $ 2,500 | $ 900 |