Stock-Based Compensation (Details Textual)						1 Months Ended						3 Months Ended								12 Months Ended
	Jan. 05, 2015 USD ($) Directors shares	Sep. 01, 2014 USD ($) shares	Jul. 30, 2014 USD ($) shares	Aug. 06, 2013 USD ($) shares	Aug. 01, 2013 USD ($) shares	Jul. 23, 2015 USD ($) Directors shares	May. 31, 2014	Jan. 31, 2014 USD ($) shares	May. 31, 2013	Apr. 15, 2013 USD ($)	May. 31, 2011 USD ($)	Jul. 31, 2015 USD ($)	Apr. 30, 2015 USD ($)	Jan. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Jul. 31, 2014 USD ($)	Apr. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	Oct. 31, 2013 USD ($) shares	Jul. 31, 2015 USD ($) $ / shares shares	Jul. 31, 2014 USD ($) shares	Jul. 31, 2013 USD ($) $ / shares shares	Jul. 31, 2012 USD ($)
Stock-Based Compensation (Textual)
Stock-based compensation																					$ 12,000	$ 675,000
Intrinsic value of options exercised																				$ 186,976
Closing stock price | $ / shares																				$ 23.57
Selling, general and administrative												$ 2,870,000	$ 1,353,000	$ 1,605,000	$ 1,103,000	$ 725,000	$ 665,000	$ 1,042,000	$ 569,000	$ 6,931,000	3,001,000	$ 3,115,000
Unrecognized compensation cost related to non-vested restricted share value												$ 3,300,000								3,300,000
Unrecognized compensation cost in fiscal 2016																				1,810,000
Unrecognized compensation cost in fiscal 2017																				985,000
Unrecognized compensation cost in fiscal 2018																				400,000
Unrecognized compensation cost in fiscal 2019																				64,000
Stock Option [Member]
Stock-Based Compensation (Textual)
Selling, general and administrative																				$ 3,346,977	$ 758,343
IDT[Member]
Stock-Based Compensation (Textual)
Common stock options purchase | shares																						641,567
Common stock shares outstanding option, percentage																						10.00%
Straight Path IP Group [Member]
Stock-Based Compensation (Textual)
Estimated value of grant option Srtaight Path IP										$ 13,318
Stock option purchase of consultant, percentage										0.50%
Consultant stock option vested percentage							33.40%		33.40%	33.20%
Expected volatility										51.00%
Discount rate										0.80%
Expected term										4 years
Stock-based compensation																						$ 13,000	$ 52,000
Straight Path IP Group [Member] | Former CEO [Member]
Stock-Based Compensation (Textual)
Estimated value of grant option Srtaight Path IP											$ 200,000
Stock option purchase of consultant, percentage											5.00%
Grant options equity outstanding of Srtaight Path IP											$ 400,000
Expected volatility											49.00%
Discount rate											2.20%
Expected term											6 years
Common Class B [Member]
Stock-Based Compensation (Textual)
Common stock shares reserved | shares																						678,532
Common stock available for grant of awards by an additional shares | shares																			350,000
Common stock options purchase | shares																						32,155
Exercise option price per share | $ / shares																						$ 5.67
Number of share granted for service | shares				10,100																	5,500
Common stock with aggregate fair value			$ 1,214,000	$ 50,000	$ 1,519,000																$ 91,000
Restricted common stock shares description			One-third of both grants of restricted shares vested on March 30, 2015 and the remaining vest as to approximately one-third of the granted shares on each of February 1, 2016 and 2017.	These restricted shares vest as to one-third of the granted shares in each of August 2014, 2015 and 2016.																	These restricted shares vested as to one-half of the granted shares on each of January 31, 2015 and July 31, 2015.
Resticted common stock non vested -shares | shares																				386,560
Common Class B [Member] | Jonathan Rand [Member]
Stock-Based Compensation (Textual)
Number of share granted for service | shares			52,000		38,268
Common Class B [Member] | Davidi Jonas [Member]
Stock-Based Compensation (Textual)
Number of share granted for service | shares			71,000		229,608	60,000
Common stock with aggregate fair value						$ 1,494,900
Common Class B [Member] | Non Employee Director [Member]
Stock-Based Compensation (Textual)
Number of directors | Directors	3
Number of share granted for service | shares	24,000				3,750			24,000
Common stock with aggregate fair value	$ 438,000				$ 21,263			$ 197,000
Common Class B [Member] | Two Employees [Member]
Stock-Based Compensation (Textual)
Number of directors | Directors						2
Number of share granted for service | shares						22,500
Common stock with aggregate fair value						$ 685,800
Restricted common stock shares description						These restricted shares vest as to one-third of the granted shares on each of October 16, 2015, 2016 and 2017.
Common Class B [Member] | One Employee [Member]
Stock-Based Compensation (Textual)
Number of directors | Directors						1
Number of share granted for service | shares						5,000
Common stock with aggregate fair value						$ 152,400
Restricted common stock shares description						These restricted shares vest as to one-half of the granted shares on each of October 16, 2016 and 2017.
Common Class B [Member] | Jerry Pi [Member]
Stock-Based Compensation (Textual)
Number of share granted for service | shares		60,000				30,000
Common stock with aggregate fair value		$ 573,000				$ 914,400
Restricted common stock shares description		These restricted shares vest as to one-third of the granted shares on each of October 16, 2015, September 1, 2016 and September 1, 2017.				These restricted shares vest as to one-third of the granted shares on each of October 16, 2016, 2017 and 2018.