Leases (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jan. 31, 2020	Jan. 31, 2020
Leases [Abstract]
Operating lease cost		$ 59	$ 117
Other lease cost, net	[1]	37	69
Total lease cost		$ 96	$ 186

[1] Other lease cost, net includes short-term lease costs and variable lease costs, which are immaterial.