Employee Incentive Plans - Narrative (Details)		1 Months Ended		3 Months Ended		6 Months Ended			12 Months Ended
	Feb. 17, 2017 USD ($) shares	Mar. 31, 2017 offering_period	Feb. 28, 2017 USD ($) shares	Jul. 31, 2018 USD ($) $ / shares shares	Jul. 31, 2017 USD ($) shares	Jul. 31, 2018 USD ($) incentive_plan $ / shares shares	Jul. 31, 2017 USD ($) $ / shares shares		Jan. 31, 2018 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans | incentive_plan						2
Options to purchase common stock outstanding (in shares) | shares				20,898,490		20,898,490			24,917,045
Weighted average grant date fair value of options granted (in dollars per share) | $ / shares						$ 17.21	$ 5.36
Grant date fair value of vested stock options				$ 7,800,000	$ 8,400,000	$ 13,500,000	$ 13,000,000
Intrinsic value of options exercised				73,200,000	$ 5,300,000	155,100,000	19,300,000
Unrecognized stock-based compensation expense related to stock options				$ 50,900,000		$ 50,900,000
Number of options, granted (in shares) | shares						684,500
Issuance of common stock under employee stock purchase plan						$ 6,700,000
General and administrative expense recognized						$ 1,008,000	$ 0	[1]
Class A Common Stock | Contribution of Nonmonetary Assets to Charitable Organization
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued as charitable contribution (in shares) | shares				20,000	0	20,000	0
General and administrative expense recognized				$ 1,000,000	$ 0	$ 1,000,000	$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period									3 years 5 months 9 days
Unrecognized compensation costs related to unvested restricted stock units									$ 180,200,000
Granted during period (in shares) | shares						2,752,588
Vested during period (in shares) | shares						542,969
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						2 years 3 months 4 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						7 months 28 days
Unrecognized compensation costs related to unvested restricted stock units				$ 5,300,000		$ 5,300,000
ESPP offering period		12 months
Number of offering periods | offering_period		2
ESPP length of purchase period		6 months
Shares issued under ESPP (in shares) | shares				434,640		434,640
Weighted average price, shares issued under ESPP (in usd per share) | $ / shares				$ 15.31		$ 15.31
Stormpath Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-combination service consideration	$ 3,700,000
Stormpath Inc. | Restricted common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted during period (in shares) | shares	800,000
Shares issued fair value	$ 8,600,000
Stormpath Inc. | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						7 months 6 days
Unrecognized compensation costs related to unvested restricted stock units				$ 1,200,000		$ 1,200,000
Vested during period (in shares) | shares						400,000
Stormpath Inc. | Stormpath Workforce
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense related to stock options			$ 2,100,000	1,400,000		$ 1,400,000
Shares issued fair value	9,100,000
Pre-combination service consideration	$ 1,500,000
Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						1 year 4 days
Unrecognized compensation costs related to unvested restricted stock units			$ 5,500,000	$ 1,400,000		$ 1,400,000
Granted during period (in shares) | shares			598,500
Shares issued fair value			$ 6,600,000
Vested during period (in shares) | shares						210,850
Stormpath Inc. | Stormpath Workforce | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average stock-based compensation recognition period						1 year 10 months 24 days
Shares issued fair value			$ 2,500,000
Stock-based compensation vesting period			4 years
Number of options, granted (in shares) | shares			518,900
Minimum | Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation vesting period			2 years
Maximum | Stormpath Inc. | Stormpath Workforce | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation vesting period			3 years
2009 Stock Plan | Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock outstanding (in shares) | shares				20,133,894		20,133,894
2017 Equity Incentive Plan | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock outstanding (in shares) | shares				764,596		764,596

[1] See Note 2 for a summary of adjustments.