Stock-Based Compensation (Tables)

The following table is a summary of stock option activity for the year ended January 31, 2021:


	Number of Shares	Weighted- Average Exercise Price Per Share
	(in thousands)








Options outstanding at January 31, 2020	14,689	$	5.52
Granted	97	$	64.64
Exercised	(7,752)	$	3.72
Canceled	(388)	$	9.66
Options outstanding at January 31, 2021	6,646	$	8.24
Options vested and expected to vest at January 31, 2021	6,646	$	8.24
Options exercisable at January 31, 2021	3,377	$	5.13

The following table is a summary of RSU and PSU activities for the year ended January 31, 2021:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
	(in thousands)




RSUs and PSUs outstanding at January 31, 2020	6,063	$	29.82
Granted	4,743	$	85.13
Released	(1,994)	$	34.15
Forfeited	(363)	$	43.31
RSUs and PSUs outstanding at January 31, 2021	8,449	$	59.27
RSUs and PSUs expected to vest at January 31, 2021	8,449	$	59.27

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


	Year Ended January 31,
	2021		2020		2019

	(in thousands)
Subscription cost of revenue	$	11,705	$	5,226	$	689
Professional services cost of revenue	6,005		2,486		205
Sales and marketing	50,557		23,919		5,175
Research and development	40,274		15,403		7,815
General and administrative	41,134		32,906		6,621
Total stock-based compensation expense	$	149,675	$	79,940	$	20,505

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


	Year Ended January 31,
	2021		2020		2019
Expected term (in years)	3.17-6.05		6.05		6.05-7.52
Risk-free interest rate	0.2% - 0.4%		2.0% - 2.4%		2.6% - 3.1%
Expected stock price volatility	35.8% - 37.3%		37.7% - 37.9%		37.8% - 38.9%
Dividend yield	—	%	—	%	—	%