Summary of Business and Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended			9 Months Ended
	Oct. 31, 2020	Apr. 30, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Jan. 31, 2020
Summary Of Business And Significant Accounting Policies [Line Items]
Proceeds from employee stock sales to be remitted				$ 295,900,000	$ 48,500,000
Payments to acquire equity securities without readily determinable fair value		$ 8,000,000.0	$ 3,000,000.0
Unrealized gain (loss) on investments				2,500,000
Equity securities without readily determinable fair value, amount	$ 13,500,000			13,500,000		$ 3,000,000.0
Goodwill, impairment loss	0			0
Impairment of intangible assets (excluding goodwill)	0			0
Convertible Promissory Note | Convertible Debt Receivable
Summary Of Business And Significant Accounting Policies [Line Items]
Receivable with imputed interest, face amount		$ 5,000,000.0
Receivable with imputed interest, term		5 years
Receivable with imputed interest, interest rate		3.00%
Receivable with imputed interest, fair value disclosure	$ 5,100,000			$ 5,100,000