Business and Summary of Significant Accounting Policies - Narrative (Details)			1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 01, 2018	Mar. 31, 2018 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) $ / shares shares	Jul. 31, 2018 USD ($) shares	Oct. 31, 2017 USD ($)	Jul. 31, 2018 USD ($) segment shares	Jul. 31, 2017 USD ($) shares	Jul. 31, 2016 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reverse stock split, ratio			0.6667
Sale of stock, number of shares issued in transaction (in shares) | shares			13,800,000
Sale of stock, price per share (in dollars per share) | $ / shares		$ 16.00	$ 16.00
Sale of stock, net proceeds			$ 205,300,000
Payments of stock issuance costs			$ 15,500,000			$ 4,336,000	$ 31,000	$ 0
Offering costs		$ 6,500,000				6,500,000	$ 1,200,000
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares) | shares		72,500,750
Conversion ratio	1		1				1
Foreign currency loss						$ 100,000	$ 100,000	300,000
Number of reportable segments | segment						1
Number of operating segments | segment						1
Contract with customer, liability, revenue recognized						$ 85,300,000	58,500,000	40,700,000
Revenue, remaining performance obligation				$ 397,900,000		397,900,000
Capitalized contract cost, amortization period				5 years
Accrued sales commission				$ 10,000,000		10,000,000	5,400,000
Investment impairment						0	0
Restricted cash				600,000		600,000	600,000
Capitalized software costs				1,800,000		1,800,000	400,000	800,000
Capitalized software, amortization expense				$ 900,000		$ 900,000	1,200,000	1,000,000
Leasehold improvements								1,500,000
Requisite service period						4 years
Cumulative effect of new accounting principle							0
Share-based compensation, excess tax benefit, amount					$ 900,000
Advertising expense						$ 3,400,000	$ 1,800,000	$ 1,800,000
Preferred stock, shares issued (in shares) | shares				0		0	0
Redeemable convertible preferred stock, shares outstanding (in shares) | shares				0		0	0
Subscription and Support | Transferred over Time | Sales Revenue, Net | Product Concentration Risk
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk percentage						99.00%	99.00%	99.00%
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle							$ 438,000
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract with customer, term of contract						1 year
Contracts with customers, payment terms						30 days
Estimated Useful Life						2 years
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract with customer, term of contract						3 years
Estimated Useful Life						5 years
ASU 2016-09 | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle					$ 400,000
Capitalized internal-use software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated Useful Life						3 years