Net Loss per Share - Schedule of Potentially Dilutive Securities Excluded from Computation of Net Loss per Share (Details) - shares shares in Thousands	3 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share (in shares)	54,821	68,883
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share (in shares)	39,837	56,884
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share (in shares)	14,200	11,118
Unvested restricted common stock and early exercised stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share (in shares)	738	829
Employee stock purchase rights under the 2020 ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted net loss per share (in shares)	46	52