Redeemable Convertible Preferred Stock (Details) $ in Thousands		3 Months Ended	9 Months Ended
	Sep. 18, 2020 USD ($) shares	Oct. 31, 2020 USD ($) shares	Oct. 31, 2020 USD ($) shares	Jul. 31, 2020 shares	Jan. 31, 2020 shares	Oct. 31, 2019 shares	Jul. 31, 2019 shares	Jan. 31, 2019 shares
Temporary Equity [Line Items]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)		(182,271,099)	(182,271,099)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering | $		$ 1,415,047	$ 1,415,047
Conversion of redeemable convertible preferred stock to common stock upon initial public offering | $		$ (1,415,047)	$ (1,415,047)
Redeemable convertible preferred stock, shares issued (in shares)		0	0		169,921,272
Redeemable convertible preferred stock, shares outstanding (in shares)		0	0	182,271,099	169,921,272	169,921,272	169,159,160	168,309,042
Class B Common Stock
Temporary Equity [Line Items]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)	182,271,099
Conversion ratio	1
Conversion of redeemable convertible preferred stock to common stock upon initial public offering | $	$ 1,400,000
Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Conversion of redeemable convertible preferred stock to common stock upon initial public offering (in shares)	(182,271,099)
Conversion of redeemable convertible preferred stock to common stock upon initial public offering | $	$ (1,400,000)
Redeemable convertible preferred stock, shares issued (in shares)		0	0
Redeemable convertible preferred stock, shares outstanding (in shares)		0	0