Investments in Marketable Securities (Details 2) (USD $)
In Thousands, unless otherwise specified |
Jan. 31, 2013
|
Jan. 31, 2012
|
---|---|---|
Amortized Cost | $ 119,911 | $ 92,492 |
Gross Unrealized Gains | 83 | 88 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 119,994 | 92,580 |
Cash [Member]
|
||
Amortized Cost | 104,109 | 74,226 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 104,109 | 74,226 |
Cash Equivalents [Member]
|
||
Amortized Cost | 2,612 | 6,359 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 2,612 | 6,359 |
Cash and Cash Equivalents [Member]
|
||
Amortized Cost | 106,721 | 80,585 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 106,721 | 80,585 |
Us Government Agency Issues Short Term [Member]
|
||
Amortized Cost | 6,043 | 6,781 |
Gross Unrealized Gains | 61 | 68 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 6,104 | 6,849 |
Us Government Agency Issues Long Term [Member]
|
||
Amortized Cost | 7,147 | 4,126 |
Gross Unrealized Gains | 22 | 14 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 7,169 | 4,140 |
Corporate Debt Securities Short Term [Member]
|
||
Amortized Cost | 0 | 1,000 |
Gross Unrealized Gains | 0 | 6 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 0 | 1,006 |
Corporate Debt Securities Long 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 | 6,043 | 7,781 |
Gross Unrealized Gains | 61 | 74 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 6,104 | 7,855 |
Marketable Securities Long Term [Member]
|
||
Amortized Cost | 7,147 | 4,126 |
Gross Unrealized Gains | 22 | 14 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | $ 7,169 | $ 4,140 |