Property, Buildings and Equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 21,422	$ 24,418
Accumulated depreciation and amortization	(16,994)	(18,324)
Property, buildings and equipment, net	4,428	6,094
Insurance proceeds received	0	358	$ 0
Sale of property related building improvements and fixtures	1,495	5	$ 255
Gain on sale on property	100
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	393	393
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,338	9,700
Field Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,267	2,222
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,339	4,439
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,107	3,105
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,264	2,683
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,331	1,333
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 383	$ 543