Revenues in Wireless Spectrum (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	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, 2016	Jul. 31, 2015	Jul. 31, 2014
Summary of revenues and gain on sale
Revenues	$ 122	$ 219	$ 112	$ 1,703	$ 2,769	$ 2,867	$ 2,781	$ 4,823	$ 3,303	$ 913	$ 453	$ 127	$ 2,156	$ 13,240	$ 4,796
Straight Path Spectrum [Member]
Summary of revenues and gain on sale
Revenues													461	426	424
Straight Path Spectrum [Member] | Customer 1 [Member]
Summary of revenues and gain on sale
Revenues													165	165	165
Straight Path Spectrum [Member] | Customer 2 [Member]
Summary of revenues and gain on sale
Revenues													86	87	114
Straight Path Spectrum [Member] | Customer 3 [Member]
Summary of revenues and gain on sale
Revenues													$ 58	$ 70	$ 53