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Marketable Securities (Details 2) - USD ($) $ in Thousands | Jul. 31, 2015 | Jul. 31, 2014
--- | --- | ---
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | $ 587 |
Fair Value | 13,284 |
Certificates Of Deposit [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | 2 |
Fair Value | 2,194 |
International agency notes [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | 1 |
Fair Value | 1,119 |
Mutual funds [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | 18 |
Fair Value | 4,982 |
Straight Path Communications Inc. common stock [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | 563 |
Fair Value | 1,523 |
Equity Securities [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses |  | $ 9
Fair Value |  | $ 22
Municipal Bonds [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Unrealized Losses | 3 |
Fair Value | $ 3,466 |

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