Business Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Summary of operating results for the business segments
Revenues	$ 2,769	$ 2,867	$ 2,781	$ 4,823	$ 3,303	$ 913	$ 453	$ 127	$ 13,240	$ 4,796	$ 1,130
Income (loss) from operations									$ 266	$ (692)	(3,615)
Gain on sale of rights in wireless spectrum included in loss from operations											150
Loss on settlement of Straight Path Spectrum legal proceedings included in loss from operations											(1,150)
Straight Path Spectrum [Member]
Summary of operating results for the business segments
Revenues									$ 426	$ 424	525
Income (loss) from operations									(1,641)	(495)	(1,891)
Gain on sale of rights in wireless spectrum included in loss from operations											150
Loss on settlement of Straight Path Spectrum legal proceedings included in loss from operations											(1,150)
Straight Path IP Group [Member]
Summary of operating results for the business segments
Revenues									12,814	4,372	605
Income (loss) from operations									$ 1,907	$ (197)	$ (1,724)
Gain on sale of rights in wireless spectrum included in loss from operations
Loss on settlement of Straight Path Spectrum legal proceedings included in loss from operations