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Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions |  |  |  |  | 12 Months Ended
--- | --- | --- | --- | --- | ---
Sep. 28, 2017 | May 02, 2017 | Dec. 14, 2016 | Jun. 07, 2016 | Jul. 31, 2017 | Jul. 31, 2016 | Jul. 31, 2015
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Options exercise price |  |  |  |  | $ 13.38 |  |
Option granted to purchase common stock |  |  |  |  | 1,000,000 |  |
Stock Options [Member] |  |  |  |  |  |  |
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Total intrinsic value of options exercised during the period |  |  |  |  | $ 0.4 |  | $ 1.3
Total unrecognized compensation cost |  |  |  |  | $ 3.4 |  |
Non-vested stock options, weighted-average period |  |  |  |  | 1 year 6 months |  |
Reduction of exercise price |  |  |  | $ 2.25 |  |  |
Restricted Stock [Member] |  |  |  |  |  |  |
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Non-vested stock options, weighted-average period |  |  |  |  | 8 months 12 days |  |
Total unrecognized non-vested stock-based compensation |  |  |  |  | $ 2.4 |  |
Total grant date fair value of shares vested |  |  |  |  | $ 4.1 | $ 1.3 | $ 5.6
Class B Common Stock [Member] |  |  |  |  |  |  |
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Additional shares available stock option incentive plan for grants |  |  | 100,000 |  |  |  |
Shares of common stock reserved for award under 2015 stock option and incentive plan |  |  |  |  | 700,000 |  |
Shares of common stock available for future grants |  |  |  |  | 100,000 |  |
Class B Common Stock [Member] | Subsequent Event [Member] |  |  |  |  |  |  |
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Additional shares available stock option incentive plan for grants | 300,000 |  |  |  |  |  |
Class B Common Stock [Member] | Stock Options [Member] |  |  |  |  |  |  |
Stock-Based Compensation (Textual) |  |  |  |  |  |  |
Options expire date |  | May 01, 2022 |  |  |  |  |
Fair value of options on grant date |  | $ 3.3 |  |  |  |  |
Options exercise price |  | $ 14.93 |  |  |  |  |
Option granted to purchase common stock |  | 1,000,000 |  |  |  |  |
Repurchase right number of shares year 1 |  | 333,333 |  |  |  |  |
Repurchase right number of shares year 2 |  | 333,333 |  |  |  |  |
Repurchase right number of shares year 3 |  | 333,334 |  |  |  |  |

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- Definition Repurchase right number of shares year 1. + References No definition available. + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Unrecognized cost of unvested options awarded to employees as compensation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Date the equity-based award expires, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Net number of share options (or share units) granted during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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