Property, Buildings and Equipment, net (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Apr. 30, 2016 USD ($) Building	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2014 USD ($)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 24,418	$ 30,552
Accumulated depreciation and amortization		(18,324)	(23,438)
Property, buildings and equipment, net		6,094	7,114
Insurance proceeds received		358	0	$ 0
Number of buildings damaged | Building	2
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		9,700	10,368
Field Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		2,222	2,786
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		4,439	4,685
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		3,105	6,112
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		2,683	4,076
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		1,333	1,439
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 543	$ 693
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment, net	$ 1,900
Impairment loss	400
Insurance proceeds received	$ 400