Description of Business and Summary of Significant Accounting Policies (Details) - shares shares in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Shares excluded from the calculations of diluted loss per share	345	199	335
Non-vested restricted Class B common stock [Member]
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Shares excluded from the calculations of diluted loss per share	251	196	331
Warrants [Member]
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Shares excluded from the calculations of diluted loss per share	65
Stock options [Member]
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Shares excluded from the calculations of diluted loss per share	29	3	4