Convertible Preferred Stock, Stockholders’ Equity (Deficit) and Equity Incentive Plan (Tables)

12 Months Ended

Jan. 31, 2021

Equity [Abstract]

Schedule of Stock by Class Reserved for Future Issuance

We have the following shares of Class A common stock reserved for future issuance:

	As of January 31,
	2021	2020
Stock options outstanding	9,239,504	16,833,009
RSUs outstanding	4,510,730	1,964,668
ESPP purchase rights outstanding	724,883	1,323,662
Remaining shares available for future issuance under the 2011 and 2019 plan	44,584,783	33,604,587
Remaining shares available for future issuance under the ESPP	9,648,574	7,186,070
Total shares of Class A common stock reserved	68,708,474	60,911,996

Summary of Stock Option Activity Under Equity Incentive Plan

A summary of stock option activity under our equity incentive plan and related information is as follows:

	Stock Options
	Outstanding Stock Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
	(in thousands, except share, life and per share data)
Balance as of January 31, 2020	16,833,009	$	5.73	7.6	$	1,191,881
Granted	—	$	—
Exercised	(7,378,477)	$	3.87		$	1,786,657
Canceled/forfeited/expired	(215,028)	$	8.05
Balance as of January 31, 2021	9,239,504	$	7.17	7.0	$	3,371,457
Vested and exercisable as of January 31, 2021	4,641,908	$	3.98	6.6	$	1,708,663

There were no options granted for the fiscal year ended January 31, 2021.

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The Black-Scholes assumptions used to value the employee options at the grant dates are as follows:

	Year ended January 31,
		2020	2019
Expected term (years)		5.0 - 6.1	5.0 - 6.2
Expected volatility		49.9% - 53.2%	44.6% - 48.2%
Risk-free interest rate		1.6% - 2.5%	2.6% - 3.1%
Expected dividend yield		—	—

Summary of Restricted Stock Units (RSUs) Activity Under Equity Incentive Plan

A summary of RSU activity under our equity incentive plan and related information is as follows:

	RSUs
	Unvested RSUs	Weighted-Average Grant Date Fair Value Per Share
Unvested as of January 31, 2020	1,964,668	$	79.11
Granted	3,351,979	$	241.32
Vested	(625,163)	$	86.29
Canceled/forfeited	(180,754)	$	181.18
Unvested as of January 31, 2021	4,510,730	$	194.57

Summary of Assumptions for Estimating Fair Value of ESPP Purchase Rights

We estimated the fair value of ESPP purchase rights using a Black-Scholes option-pricing model with the following assumptions:

	Year ended January 31,
	2021	2020
Expected term (years)	0.5 - 2.1	0.5 - 2.1
Expected volatility	40.3% - 75.0%	40.3% - 56.2%
Risk-free interest rate	0.1% - 2.5%	1.5% - 2.5%
Expected dividend yield	—	—

Summary of Stock-based Compensation Expense by Line Item

The stock-based compensation expense by line item in the accompanying consolidated statements of operations is summarized as follows:

	Year Ended January 31,
	2021		2020		2019
	(in thousands)
Cost of revenue	$	34,960	$	7,860	$	1,119
Research and development	50,161		11,645		1,369
Sales and marketing	146,377		41,465		3,540
General and administrative	44,320		12,139		2,913
Total stock-based compensation expense	$	275,818	$	73,109	$	8,941