Income Taxes (Details 4) $ in Thousands	12 Months Ended
	Jul. 31, 2020 USD ($)
Operating Loss Carryforwards [Line Items]
Total R&D credit carryforwards	$ 84,440
U.S. Federal
Operating Loss Carryforwards [Line Items]
Total R&D credit carryforwards	46,271
California
Operating Loss Carryforwards [Line Items]
Total R&D credit carryforwards	$ 38,169