Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Jan. 31, 2013	Apr. 30, 2014	Apr. 30, 2013	Jul. 31, 2012
Summary of operating results for the business segments
Revenues	$ 913	$ 285		$ 1,493	$ 982
Loss from operations	(177)	(888)		(1,519)	(2,769)
Gain on sale of rights in wireless spectrum					150
Straight Path Spectrum [Member]
Summary of operating results for the business segments
Revenues	109	120		325	397
Loss from operations	(117)	(750)		(352)	(670)
Gain on sale of rights in wireless spectrum			200		150	5,300
Straight Path IP [Member]
Summary of operating results for the business segments
Revenues	804	165		1,168	585
Loss from operations	(60)	(138)		(1,167)	(2,099)
Gain on sale of rights in wireless spectrum