Concentration of Customers (Details) (Straight Path Spectrum [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2015	Apr. 30, 2014
Customer 1 [Member]
Revenue	$ 41	$ 41	$ 124	$ 124
Customer 2 [Member]
Revenue	21	28	66	87
Customer 3 [Member]
Revenue	$ 10	$ 10	$ 29	$ 29