The estimated future forfeitures related to total unrecognized stock-based compensation cost.

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The portion of stock-based compensation that is capitalized in ending inventory.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount, after tax, of expense for award under share-based payment arrangement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Discount rate from fair value on purchase date that participants pay for shares.

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Number of options outstanding, including both vested and non-vested options.

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Stock-Based Compensation (Expenses) (Details) - USD ($)	3 Months Ended
Stock-Based Compensation (Expenses) (Details) - USD ($)	Oct. 31, 2021	Oct. 31, 2020	Jul. 31, 2021
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 921,000	$ 699,000
Estimated Income tax benefit	(193,000)	(144,000)
Net stock-based compensation expense	728,000	555,000
Total remaining unrecognized compensation cost related to the unvested stock-based awards	13,766,000
Estimated forfeitures related to unvested stock-based awards	$ 1,217,000
Weighted average number of years net compensation cost is expected to be recognized over	3 years 4 months 24 days
Stock-based compensation capitalized and included in ending inventory	$ 48,000		$ 48,000
Stock options
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 78,000	120,000
Number of stock-based awards outstanding at period end (in shares)	1,015,965		1,073,435
Performance shares
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 349,000	222,000
RSUs and restricted stock
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	856,000	922,000
ESPP
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 55,000	51,000
Discount offered to employees participating in the ESPP as a percentage of market price	15.00%
Share units
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ (417,000)	(616,000)
2000 Stock Incentive Plan \| Stock options
Stock-based Compensation Expenses
Number of stock-based awards outstanding at period end (in shares)	1,015,965
2000 Stock Incentive Plan \| Stock appreciation rights (SARs)
Stock-based Compensation Expenses
Number of stock-based awards outstanding at period end (in shares)	0		0
Cost of sales
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 73,000	73,000
Selling, general and administrative expenses
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	772,000	542,000
Research and development expenses
Stock-based Compensation Expenses
Stock-based compensation expense (benefit) before income tax benefit	$ 76,000	$ 84,000