Stock-Based Compensation (Expenses) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022	Oct. 31, 2022	Jul. 31, 2022
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 1,268,000	$ 1,983,000	$ 2,172,000	$ 2,904,000
CEO transition costs related to equity-classified stock-based awards	0	7,388,000	3,764,000	7,388,000
Total stock-based compensation expense before income tax benefit	1,268,000	9,371,000	5,936,000	10,292,000
Estimated Income tax benefit	(293,000)	(1,030,000)	(786,000)	(1,223,000)
Net stock-based compensation expense	975,000	8,341,000	5,150,000	9,069,000
Total remaining unrecognized compensation cost related to the unvested stock-based awards	10,669,000		10,669,000
Estimated forfeitures related to unvested stock-based awards	789,000		$ 789,000
Weighted average number of years net compensation cost is expected to be recognized over			2 years 7 months 6 days
Stock-based compensation capitalized and included in ending inventory	48,000		$ 48,000			$ 48,000
Stock options
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 19,000	364,000	$ 44,000	442,000
Number of stock-based awards outstanding at period end (in shares)	291,620		291,620		474,020	483,480
Performance shares
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 281,000	364,000	$ 355,000	713,000
RSUs and restricted stock
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	937,000	1,200,000	1,711,000	1,639,000
ESPP
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 31,000	55,000	$ 62,000	110,000
Discount offered to employees participating in the ESPP as a percentage of market price			15.00%
2000 Stock Incentive Plan | Stock options
Stock-based Compensation Expenses
Number of stock-based awards outstanding at period end (in shares)	291,620		291,620
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			0
Cost of sales
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 153,000	76,000	$ 311,000	149,000
Selling, general and administrative expenses
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	1,015,000	1,836,000	1,663,000	2,608,000
Research and development expenses
Stock-based Compensation Expenses
Stock-based compensation expense before CEO transition costs	$ 100,000	$ 71,000	$ 198,000	$ 147,000