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

12 Months Ended

Jan. 31, 2020

Equity [Abstract]

Schedule of Stock by Class

Convertible preferred stock consisted of the following as of January 31, 2019 and as of immediately prior to the automatic conversion of convertible preferred stock into common stock:

	As of January 31, 2019
	Designated Shares Authorized	Shares Issued and Outstanding	Aggregate Liquidation Preference
	(in thousands, except share data)
Series A	67,083,500	61,717,700	$	9,258
Series B	25,857,784	25,857,784	6,500
Series C	34,363,256	34,363,256	30,000
Series D	30,800,000	30,727,064	114,966
Total convertible preferred stock	158,104,540	152,665,804	$	160,724

Schedule of Stock by Class Reserved for Future Issuance

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

	As of January 31,
	2020	2019
Conversion of convertible preferred stock	—	152,665,804
Stock options outstanding	16,833,009	35,064,465
RSUs outstanding	1,964,668	—
ESPP purchase rights outstanding	1,323,662	—
Remaining shares available for future issuance under the 2011 and 2019 plan	33,604,587	1,848,100
Remaining shares available for future issuance under the ESPP	7,186,070	—
Total shares of common stock reserved	60,911,996	189,578,369

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, 2019	35,064,465	$	1.48	6.8	$	534,572
Granted	1,576,150	$	36.86
Exercised	(19,003,652)	$	0.49		$	767,336
Canceled/forfeited/expired	(803,954)	$	5.15
Balance as of January 31, 2020	16,833,009	$	5.73	7.6	$	1,191,881
Vested and exercisable as of January 31, 2020	7,248,393	$	1.78	6.8	$	540,222

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	2018
Expected term (years)	5.0 - 6.1	5.0 - 6.2	5.6 - 6.7
Expected volatility	49.9% - 53.2%	44.6% - 48.2%	47.7% - 52.0%
Risk-free interest rate	1.6% - 2.5%	2.6% - 3.1%	1.8% - 2.3%
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, 2019	—	$	—
Granted	2,048,248	$	79.22
Vested	(31,649)	$	78.23
Canceled/forfeited	(51,931)	$	84.00
Unvested as of January 31, 2020	1,964,668	$	79.11

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, 2020
Expected term (years)	0.5 - 2.1
Expected volatility	40.3% - 56.2%
Risk-free interest rate	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,
	2020		2019		2018
	(in thousands)
Cost of revenue	$	7,860	$	1,119	$	204
Research and development	11,645		1,369		360
Sales and marketing	41,465		3,540		812
General and administrative	12,139		2,913		8,953
Total stock-based compensation expense	$	73,109	$	8,941	$	10,329