Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Operating Loss Carryforwards [Line Items]
Discrete tax benefit from Tax Reform			$ 11,792,000
Enacted federal statutory income tax rate	21.00%	21.00%	27.00%
Net deferred tax liabilities	$ 16,471,000	$ 11,396,000
Federal, state and foreign research and experimentation credits	19,656,000	18,183,000
Minimum taxable income in the future to fully utilize net deferred tax assets	174,900,000
Unrecognized tax benefits, including interest	8,345,000	7,215,000
Interest accrued relating to income taxes	75,000	12,000
Unrecognized tax benefits that would positively impact our effective tax rate, if recognized	7,700,000	6,670,000
Non-current income taxes payable
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, including interest	1,963,000	325,000
Non-current deferred tax assets
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, including interest	6,382,000	6,890,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	1,166,000	$ 1,085,000
Federal, state and foreign research and experimentation credits	2,471,000
Operating loss carryforwards, valuation allowance	656,000
Valuation allowance	586,000
Foreign operating loss carryforwards	1,491,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Alternative minimum tax credit carryforwards	506,000
Federal, state and foreign research and experimentation credits	9,566,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal, state and foreign research and experimentation credits	7,620,000
State and local operating loss carryforwards	2,451,000
Operating loss carryforwards, valuation allowance	2,409,000
Valuation allowance	$ 7,140,000