Income Taxes (Details 4) $ in Thousands	12 Months Ended
	Jul. 31, 2018 USD ($)
Operating Loss Carryforwards [Line Items]
Research and Development Credits Carryforwards	$ 61,605
U.S. federal [Member]
Operating Loss Carryforwards [Line Items]
Research and Development Credits Carryforwards	33,074
California [Member]
Operating Loss Carryforwards [Line Items]
Research and Development Credits Carryforwards	$ 28,531