Net Loss Per Share - Schedule of Antidilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	12,124,969	9,716,110	12,794,915	10,299,249
Stock options to purchase common stock | Class A Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	722,070	1,234,642	818,589	1,434,388
Stock options to purchase common stock | Class B Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,250,736	3,614,730	2,476,270	4,013,050
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	3,679,734	3,938,037	3,745,955	4,004,267
Early exercised stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	2,831	136	6,418
Shares underlying the conversion option of the 2024 Notes (conversion spread only prior to the adoption of ASU 2020-06) | 2024 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	27,337	925,870	308,849	841,126
Shares underlying the conversion option of the 2024 Notes (conversion spread only prior to the adoption of ASU 2020-06) | 2026 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	5,445,092	0	5,445,116	0