Business Segment Information (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 operating results for the business segments
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
Income (loss) from operations													(9,087)	266	(692)
Straight Path Spectrum [Member]
Summary of operating results for the business segments
Revenues													461	426	424
Income (loss) from operations													(5,508)	(1,641)	(495)
Straight Path IP Group [Member]
Summary of operating results for the business segments
Revenues													1,695	12,814	4,372
Income (loss) from operations													(2,688)	1,907	(197)
Straight Path Ventures [Member]
Summary of operating results for the business segments
Revenues
Income (loss) from operations													$ (891)