Fair Value Measurements (Details 1) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 3,637	$ 2,816	$ 3,619
Transfer into Level 3 from adoption of change in accounting for equity investments				2,794
Total gain (losses) recognized in "Other income (expense), net"	408	(71)	426	(49)
Balance, end of period	4,045	2,745	4,045	2,745
Change in unrealized gains or losses for the period included in earnings for assets held at the end of the period	$ 408	$ (71)	$ 426	$ (49)