Income Taxes (Narrative) (Details) - USD ($)	Jul. 31, 2023	Jul. 31, 2022
Operating Loss Carryforwards [Line Items]
Net deferred tax liabilities	$ 8,903,000	$ 14,959,000
Federal, state and foreign research and experimentation credits	19,308,000	19,476,000
Capital loss carryforward	15,582,000	15,582,000
Valuation allowance	34,478,000	31,227,000
Unrecognized tax benefits, including interest	9,166,000	10,008,000
Interest accrued relating to income taxes	210,000	330,000
Unrecognized tax benefits that would positively impact our effective tax rate, if recognized	8,286,000	9,034,000
Reasonably possible decrease in gross unrecognized tax benefits	622,000
Non-current income taxes payable
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, including interest	2,208,000	3,007,000
Non-current deferred tax assets
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, including interest	6,958,000	7,001,000
Foreign
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	591,000	$ 396,000
Federal, state and foreign research and experimentation credits	377,000
Operating loss carryforwards, valuation allowance	5,799,000
Foreign operating loss carryforwards	9,186,000
Federal
Operating Loss Carryforwards [Line Items]
Federal, state and foreign research and experimentation credits	9,995,000
State
Operating Loss Carryforwards [Line Items]
Federal, state and foreign research and experimentation credits	8,936,000
State and local operating loss carryforwards	3,864,000
Operating loss carryforwards, valuation allowance	3,757,000
State | Research and experimentation credit carryforwards
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, valuation allowance	8,246,000
State | Other
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, valuation allowance	$ 1,094,000