Equity Incentive Plans (Tables)

3 Months Ended

Mar. 31, 2022

Summary of Stock-Based Compensation Expense Related to Equity Incentive Rewards

The Company recognized total stock-based compensation cost related to equity incentive awards as follows (in thousands):

	For the Three Months Ended March 31,
	2022		2021
Stock-based compensation cost:
Stock options	$	2,161	$	3,223
Restricted stock units		22,128		11,769
Performance share units		7,813		2,832
Employee stock purchase plan		1,269		1,303
Total stock-based compensation cost	$	33,371	$	19,127

Summary of Stock Option Activity

Stock Options

The following table summarizes stock option activity for the Company’s stock-based compensation plans for the three months ended March 31, 2022:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
				Exercise		Contractual		Value
	Shares			Price		Life (in Years)		(in thousands)
Options outstanding as of January 1, 2022		2,278,789		$	33.52		6.30	$	217,824
Options granted		—		$	—
Options exercised		(107,623	)	$	21.20
Options cancelled or expired		(4,291	)	$	111.83
Options outstanding as of March 31, 2022		2,166,875		$	33.98		6.08	$	141,996
Options exercisable as of March 31, 2022		1,778,867		$	28.90		5.81	$	125,598

Summary of RSU Activity

The following table summarizes RSU activity for the Company’s stock-based compensation plans for the three months ended March 31, 2022:

				Weighted
				Average
				Grant Date Fair
	Restricted Stock Units			Value Per Share
RSUs outstanding as of January 1, 2022		2,861,963		$	99.41
RSUs granted		1,903,805			97.15
RSUs vested		(466,497	)		80.86
RSUs cancelled		(98,343	)		94.81
RSUs outstanding as of March 31, 2022		4,200,928		$	100.56

Summary of PSU Activity

The following table summarizes PSU activity for the Company’s stock-based compensation plans for the three months ended March 31, 2022:

				Weighted
				Average
				Grant Date Fair
	Performance Share Units			Value Per Share
PSUs outstanding as of January 1, 2022		114,890		$	147.26
PSUs granted		223,363			98.90
PSUs vested		(38,291	)		147.26
PSUs cancelled		—			—
PSUs outstanding as of March 31, 2022		299,962		$	111.25

2018 Employee Stock Purchase Plan

Summary of Fair Value Estimated Using Black-Scholes Option Pricing Model Assumptions

For the periods presented, the fair value of ESPP purchase rights was estimated using the Black-Scholes option-pricing model with the following assumptions:

	For the Three Months Ended March 31,
	2022		2021
Fair market value of common stock	$	111.00	$	152.35
Volatility	33%		34%
Expected term	0.5 years		0.5 years
Expected dividend yield	n/a		n/a
Risk-free interest rate	0.48%		0.08%