Income Taxes - Schedule of Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Income Tax Disclosure [Abstract]
Tax at federal statutory rate	21.00%	34.00%	34.00%
State taxes	0.00%	1.50%	1.80%
Impact of foreign rate differential	0.30%	(1.70%)	0.10%
Meals and entertainment	(1.30%)	(0.50%)	(0.50%)
Stock-based compensation	(3.80%)	(2.80%)	(4.10%)
Impact of U.S. tax reform	(58.60%)	0.00%	0.00%
Provision to return adjustments	2.80%	(0.30%)	0.00%
U.S. tax credits	3.70%	(0.00%)	(0.00%)
Change in valuation allowance	33.50%	(32.40%)	(32.50%)
Other	(1.70%)	(0.30%)	(0.50%)
Effective tax rate	(4.10%)	(2.50%)	(1.70%)