Concentration of Customers (Details) (Straight Path Spectrum [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Customer 1 [Member]
Revenue	$ 41	$ 42	$ 83	$ 83
Customer 2 [Member]
Revenue	21	35	45	59
Customer 3 [Member]
Revenue	$ 10		$ 20