Summary of Business and Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended	9 Months Ended
	Apr. 30, 2019	Apr. 23, 2019	Apr. 18, 2019	Oct. 31, 2019	Oct. 31, 2019	Oct. 31, 2018	Feb. 01, 2019	Jan. 31, 2019
Summary Of Business And Significant Accounting Policies [Line Items]
Proceeds from international employee stock sales to be remitted to employees and tax authorities				$ 48,500	$ 48,547	$ 0
Strategic investment				3,000	3,000	$ 0
Equity investment				3,000	3,000			$ 0
Operating lease, total ROU assets				53,308	53,308
Operating lease, total liabilities				$ 55,857	$ 55,857
Accounting Standards Update 2016-02
Summary Of Business And Significant Accounting Policies [Line Items]
Operating lease, total ROU assets							$ 40,500
Operating lease, total liabilities							$ 43,000
Other Assets, Non-current
Summary Of Business And Significant Accounting Policies [Line Items]
Capitalized deferred offering costs within other assets, non-current								$ 2,400
Initial public offering
Summary Of Business And Significant Accounting Policies [Line Items]
Deferred offering costs, reclassified to stockholders' equity	$ (6,400)
Initial public offering | Class A Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued (in shares)		9,911,434
Shares issued, price per share (in dollars per share)		$ 36.00
Net proceeds from shares issued		$ 340,800
Initial public offering | Class A Common Stock | Convertible Promissory Notes
Summary Of Business And Significant Accounting Policies [Line Items]
Convertible securities converted to common stock (in shares)		426,223
Initial public offering | Class A Common Stock | Underwriters
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued (in shares)			3,130,435
Shares issued, price per share (in dollars per share)			$ 36.00
Net proceeds from shares issued		$ 107,100
Initial public offering | Class B Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Convertible securities converted to common stock (in shares)		152,665,804
Private Placement | Class A Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued (in shares)		2,777,777
Aggregate proceeds from shares issued		$ 100,000
Private Placement | Class A Common Stock | Convertible Promissory Notes
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued, price per share (in dollars per share)		$ 36.00