| **Fair Value Measurements (Tables)**               | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
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| **Fair Value Disclosures [Abstract]**              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Summary Of Cash Equivalents Measured At Fair Value | The table below summarizes the Company’s cash equivalents measured at fair value (all other assets and liabilities measured at fair value are immaterial) (in thousands):              Fair Value Measurement as of April 30, 2013 Description Balance at April 30, 2013 Level 1 Level 2 Level 3  Money Market $49,025 $49,025 $— $— Commercial Paper $630 $— $630 $— Certificates of Deposit $630 $— $630 $—       Fair Value Measurement as of July 31, 2012 Description Balance at July 31, 2012 Level 1 Level 2 Level 3 Money Market $6,581 $6,581 $— $— Commercial Paper $2,441 $— $2,441 $— Certificates of Deposit $1,260 $— $1,260 $—       Fair Value Measurement as of April 30, 2012 Description Balance at April 30, 2012 Level 1 Level 2 Level 3 Money Market $1,392 $1,392 $— $— Commercial Paper $6,993 $— $6,993 $— Certificates of Deposit $1,890 $— $1,890 $— |

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| - Definition
Tabular disclosure of the inputs and valuation techniques used to measure fair value, and a discussion of changes in valuation techniques and related inputs, if any, applied during the period to each separate class of assets, liabilities, and financial instruments classified in shareholders' equity that are measured on a recurring and/or nonrecurring basis.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258
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