Stock-Based Compensation (Tables)

The following table is a summary of stock option activity for the years ended January 31, 2020, January 31, 2019, and January 31, 2018:


	Number of Shares	Weighted- Average Exercise Price Per Share
	(in thousands)
Options outstanding at February 1, 2017	19,347	$	1.10
Granted	9,691	$	2.14
Exercised	(3,733)	$	1.00
Canceled	(2,111)	$	1.57
Options outstanding at January 31, 2018	23,194	$	1.51
Granted	8,233	$	9.24
Exercised	(3,084)	$	1.26
Canceled	(1,808)	$	2.51
Options outstanding at January 31, 2019	26,535	$	3.87
Granted	1,048	$	17.76
Exercised	(11,682)	$	2.72
Canceled	(1,212)	$	6.91
Options outstanding at January 31, 2020	14,689	$	5.52
Options vested and expected to vest at January 31, 2020	14,689	$	5.52
Options exercisable at January 31, 2020	7,288	$	3.15

The following table is a summary of RSU and PSU activities for the years ended January 31, 2020:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
	(in thousands)
RSUs and PSUs outstanding at February 1, 2018	—	$	—
Granted	4,064	$	12.66
Forfeited	(5)	$	12.48
RSUs and PSUs outstanding at January 31, 2019	4,059	$	12.66
Granted	3,442	$	43.80
Released	(1,127)	$	14.00
Forfeited	(311)	$	19.37
RSUs and PSUs outstanding at January 31, 2020	6,063	$	29.82
RSUs and PSUs expected to vest at January 31, 2020	6,063	$	29.82

Stock-based compensation expense included in the consolidated statements of operations is as follows:


	Year Ended January 31,
	2020		2019		2018
	(in thousands)
Subscription cost of revenue	$	5,226	$	689	$	89
Professional services cost of revenue	2,486		205		252
Sales and marketing	23,919		5,175		1,386
Research and development	15,403		7,815		3,429
General and administrative	32,906		6,621		7,187
Total stock-based compensation expense	$	79,940	$	20,505	$	12,343

The fair value of the share purchase rights granted under the ESPP during the year ended January 31, 2020 was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:


	Year ended January 31, 2020
Expected term (in years)	0.5-2.0
Risk-free interest rate	1.6 - 2.2%
Expected stock price volatility	30.1 - 35.7%
Dividend yield	—	%

The fair value of each option was estimated on the date of grant using the following assumptions during the period:


	Year Ended January 31,
	2020		2019		2018
Expected term (in years)	6.05		6.05 - 7.52		6.05
Risk-free interest rate	2.0% - 2.4%		2.6% - 3.1%		1.9% - 2.2%
Expected stock price volatility	37.7% - 37.9%		37.8% - 38.9%		40.3% - 41.4%
Dividend yield	—	%	—	%	—	%