Income Taxes (Provision for Income Taxes Differed from Amounts Computed by the U.S. Federal Income Tax Rate) (Details) - USD ($)	12 Months Ended
Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019
Amount
Computed "expected" tax expense (benefit)	$ (15,746,000)	$ 1,955,000	$ 6,071,000
State and local income taxes, net of federal benefit	(1,371,000)	(278,000)	967,000
Stock-based compensation	(20,000)	308,000	(44,000)
Research and experimentation credits	(1,018,000)	(1,210,000)	(1,129,000)
Foreign-derived intangible income deduction	164,000	(162,000)	(632,000)
Nondeductible transaction costs	402,000	301,000	394,000
Nondeductible executive compensation	628,000	595,000	330,000
Fines and penalties	0	189,000	2,000
Audit settlements	6,000	1,000	(2,081,000)
Change in the beginning of the year valuation allowance for deferred tax assets	(805,000)	0	0
Change in valuation allowance	15,582,000	0	0
Remeasurement of deferred taxes	(224,000)	(135,000)	0
Foreign income taxes	676,000	453,000	5,000
Other, net	226,000	273,000	(14,000)
(Benefit from) provision for income taxes	$ (1,500,000)	$ 2,290,000	$ 3,869,000
Rate
Computed "expected" tax expense (benefit)	21.00%	21.00%	21.00%
State and local income taxes, net of federal benefit	1.80%	(3.00%)	3.30%
Stock-based compensation	0.00%	3.30%	(0.10%)
Research and experimentation credits	1.40%	(13.00%)	(3.90%)
Foreign-derived intangible income deduction	(0.20%)	(1.70%)	(2.20%)
Nondeductible transaction costs	(0.50%)	3.20%	1.40%
Nondeductible executive compensation	(0.80%)	6.40%	1.10%
Fines and penalties	0.00%	2.00%	0.00%
Audit settlements	0.00%	0.00%	(7.20%)
Change in the beginning of the year valuation allowance for deferred tax assets	1.10%	0.00%	0.00%
Change in valuation allowance	(20.80%)	0.00%	0.00%
Remeasurement of deferred taxes	0.30%	(1.50%)	0.00%
Foreign income taxes	(0.90%)	4.90%	0.00%
Other, net	(0.40%)	3.00%	0.00%
(Benefit from) provision for income taxes	2.00%	24.60%	13.40%

Effective Income Tax Rate Reconciliation, Change In Valuation Allowance, Amount

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