| **Fair Value Measurements**           | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Fair Value Disclosures [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| Fair Value Measurements               | Fair Value MeasurementsThe FASB issued fair value guidance that establishes how reporting entities should measure fair value for measurement and disclosure purposes. The guidance establishes a common definition of fair value applicable to all assets and liabilities measured at fair value and prioritizes the inputs into valuation techniques used to measure fair value. Accordingly, the Company uses valuation techniques which maximize the use of observable inputs and minimize the use of unobservable inputs when determining fair value. The three levels of the hierarchy are as follows:Level 1: Inputs that reflect unadjusted quoted prices in active markets that are accessible to the Company for identical assets or liabilities;Level 2: Inputs include quoted prices for similar assets and liabilities in active and inactive markets or that are observable for the asset or liability either directly or indirectly; andLevel 3: Unobservable inputs which are supported by little or no market activity.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 $—The Company’s cash equivalents are measured utilizing quoted market prices or pricing models whereby all significant inputs are either observable or corroborated by observable market data. |

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| - Definition
The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.
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