Summary of Business and Significant Accounting Policies - Additional Information (Details) - USD ($)			3 Months Ended
	Apr. 23, 2019	Apr. 18, 2019	Apr. 30, 2019	Feb. 01, 2019	Jan. 31, 2019
Summary Of Business And Significant Accounting Policies [Line Items]
Operating lease, total ROU assets			$ 48,957,000
Operating lease, total liabilities			51,749,000
Accounting Standards Update 2016-02
Summary Of Business And Significant Accounting Policies [Line Items]
Operating lease, total ROU assets				$ 40,500,000
Operating lease, total liabilities				43,000,000
Accounting Standards Update 2016-02 | Accumulated Deficit
Summary Of Business And Significant Accounting Policies [Line Items]
Impact of adoption of new standard				$ 0
Other Assets, Non-current
Summary Of Business And Significant Accounting Policies [Line Items]
Capitalized deferred offering costs within other assets, non-current					$ 2,400,000
Initial public offering
Summary Of Business And Significant Accounting Policies [Line Items]
Deferred offering costs, reclassified to stockholders' equity			$ 6,400,000
Initial public offering | Class A Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued	9,911,434
Shares issued, price per share	$ 36.00
Net proceeds from shares issued	$ 340,800,000
Initial public offering | Class A Common Stock | Underwriters
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued		3,130,435
Shares issued, price per share		$ 36.00
Net proceeds from shares issued	$ 107,100,000
Initial public offering | Class B Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Convertible securities converted to common stock, shares	152,665,804
Initial public offering | Class B Common Stock | Convertible Promissory Notes
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued, price per share	$ 36.00
Convertible securities converted to common stock, shares	426,223
Initial public offering | Convertible Preferred Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Convertible securities converted to common stock, shares	152,665,804
Private Placement | Class A Common Stock
Summary Of Business And Significant Accounting Policies [Line Items]
Shares issued	2,777,777
Shares issued, price per share	$ 36.00
Aggregate proceeds from shares issued	$ 100,000,000