Equity (Details Textual) - USD ($)			3 Months Ended
	Nov. 01, 2017	Feb. 06, 2017	Oct. 31, 2017	Oct. 31, 2016	Jul. 31, 2017
Equity (Textual)
Treasury stock, shares			40,000		40,000
Common stock issued for exercises of stock options			$ 8,000
Proceeds from warrant exercise received			1,057,000
Treasury Stock [Member]
Equity (Textual)
Number of shares held in treasury stock value			$ 427,916		$ 427,916
Treasury stock, shares			39,693		39,693
Common stock issued for exercises of stock options
Warrant [Member]
Equity (Textual)
Intrinsic value of warrants exercised			$ 4,467,330
Closing stock price			$ 181.51
Warrants Outstanding, Weighted-average Exercise Price			$ 70.35		$ 43.68
Class B common stock [Member]
Equity (Textual)
Proceeds from warrant exercise received		$ 7,500,000
Class B common stock [Member] | Common Stock [Member]
Equity (Textual)
Common stock issued for exercises of stock options, shares			1
Class B common stock [Member] | Warrant [Member]
Equity (Textual)
Common stock issued for exercises of warrants, shares			30,475,000
Proceeds from warrant exercise received			$ 1,057,000
Class B common stock [Member] | Warrant [Member] | Subsequent Event [Member]
Equity (Textual)
Issuances of warrants to purchase	3,215,000
Common stock issued for exercises of stock options	$ 283,000
Common stock issued for exercises of stock options, shares	50,000
Stock options [Member] | Class B common stock [Member]
Equity (Textual)
Common stock issued for exercises of stock options			$ 8,100,000
Common stock issued for exercises of stock options, shares			1,434,000