Convertible Preferred Stock, Stockholders’ Equity (Deficit) and Equity Incentive Plan - Summary of Restricted Stock Units Activity Under Equity Incentive Plan (Details) - RSUs	12 Months Ended
	Jan. 31, 2020 $ / shares shares
Unvested RSUs
Beginning balance (in units) | shares	0
Granted (in units) | shares	2,048,248
Vested (in units) | shares	(31,649)
Cancelled/forfeited (in units) | shares	(51,931)
Ending balance (in units) | shares	1,964,668
Weighted-Average Grant Date Fair Value Per Share
Beginning balance (in dollars per unit) | $ / shares	$ 0
Granted (in dollars per unit) | $ / shares	79.22
Vested (in dollars per unit) | $ / shares	78.23
Cancelled/forfeited (in dollars per unit) | $ / shares	84.00
Ending balance (in dollars per unit) | $ / shares	$ 79.11