Fair Value Measurements (Details 3) (USD $)
In Thousands, unless otherwise specified |
Jul. 31, 2012
|
Jan. 31, 2012
|
---|---|---|
Cost | $ 105,813 | $ 92,492 |
Gross Unrealized Gains | 104 | 88 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 105,917 | 92,580 |
Cash [Member]
|
||
Cost | 90,035 | 74,226 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 90,035 | 74,226 |
Cash Equivalents [Member]
|
||
Cost | 2,535 | 6,359 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 2,535 | 6,359 |
Cash and Cash Equivalents [Member]
|
||
Cost | 92,570 | 80,585 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 92,570 | 80,585 |
US government agency issues [Member]
|
||
Cost | 3,011 | 6,781 |
Gross Unrealized Gains | 70 | 68 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 3,081 | 6,849 |
Corporate Debt Securities [Member]
|
||
Cost | 0 | 1,000 |
Gross Unrealized Gains | 0 | 6 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 0 | 1,006 |
Us Government Agency Issues Marketable Securities Short Term [Member]
|
||
Cost | 3,011 | 7,781 |
Gross Unrealized Gains | 70 | 74 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 3,081 | 7,855 |
Us Government Agency Issues Long Term [Member]
|
||
Cost | 10,232 | 4,126 |
Gross Unrealized Gains | 34 | 14 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 10,266 | 4,140 |
Us Government Agency Issues Marketable Securities Long Term [Member]
|
||
Cost | 10,232 | 4,126 |
Gross Unrealized Gains | 34 | 14 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | $ 10,266 | $ 4,140 |