Fair Value Measurements (Details 2) (USD $)
In Thousands, unless otherwise specified |
Apr. 30, 2013
|
Jan. 31, 2013
|
---|---|---|
Amortized Cost | $ 121,346 | $ 119,911 |
Gross Unrealized Gains | 34 | 83 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 121,380 | 119,994 |
Cash [Member]
|
||
Amortized Cost | 105,525 | 104,109 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 105,525 | 104,109 |
Cash Equivalents [Member]
|
||
Amortized Cost | 3,664 | 2,612 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 3,664 | 2,612 |
Cash and Cash Equivalents [Member]
|
||
Amortized Cost | 109,189 | 106,721 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 109,189 | 106,721 |
Us Government Agency Issues Short Term [Member]
|
||
Amortized Cost | 5,030 | 6,043 |
Gross Unrealized Gains | 7 | 61 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 5,037 | 6,104 |
Us Government Agency Issues Long Term [Member]
|
||
Amortized Cost | 7,127 | 7,147 |
Gross Unrealized Gains | 27 | 22 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 7,154 | 7,169 |
Corporate Debt Securities Short Term [Member]
|
||
Amortized Cost | 0 | 0 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 0 | 0 |
Marketable Securities Short Term [Member]
|
||
Amortized Cost | 5,030 | 6,043 |
Gross Unrealized Gains | 7 | 61 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 5,037 | 6,104 |
Marketable Securities Long Term [Member]
|
||
Amortized Cost | 7,127 | 7,147 |
Gross Unrealized Gains | 27 | 22 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | $ 7,154 | $ 7,169 |