Share-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Performance-Based Option Activity

Performance-based option activity under the 2007 SIP and the 2013 SIP for the period was as follows:

	Shares			Weighted Average Exercise Price (per share)			Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Performance-based options outstanding at December 31,    2018		366,377		$	13.50			3.1	$	7.7
Granted		—			—			—		—
Exercised		(290,319	)		(13.48	)		—		—
Forfeited or expired		—			—			—		—
Performance-based options outstanding at September 30,    2019		76,058		$	13.56			2.8	$	2.7
Performance-based options exercisable at September 30,    2019		76,058		$	13.56			2.8	$	2.7

Summary of Term-Based Option Activity

Term-based option activity, including stock options under the 2007 SIP, the 2013 SIP and the 2018 EIP, for the period was as follows:

	Shares			Weighted Average Exercise Price (per share)			Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Term-based options outstanding at December 31, 2018		13,549,769		$	19.28			7.5	$	206.8
Granted		4,227,022			49.66			—		—
Exercised		(3,896,797	)		(17.34	)		—		—
Forfeited or expired		(262,923	)		(23.01	)		—		—
Term-based options outstanding at September 30, 2019		13,617,071		$	29.19			8.0	$	276.9
Term-based options exercisable at September 30, 2019		3,946,615		$	18.21			6.2	$	122.9

Summary of Restricted Stock Units Activity

Restricted stock units (“RSUs”) activity, including RSUs under the 2013 SIP and the 2018 EIP, for the period was as follows:

	Shares
RSUs outstanding at December 31, 2018		664,073
Granted		168,958
Shares issued upon vesting of RSUs		(14,394	)
Forfeited or canceled		(20,000	)
RSUs outstanding at September 30, 2019		798,637
RSUs releasable at September 30, 2019		272,045

Summary of Fair Value of Stock Purchase Rights Granted under the Global Employee Stock Purchase Plan Estimated Using Weighted-Average Assumptions

The fair value of the stock purchase rights granted under the GESPP was estimated using the following weighted-average assumptions:

	Nine Months Ended September 30, 2019
Expected volatility		34.9	%
Expected dividend rate		—
Risk-free interest rate		2.3	%
Expected term (in years)		0.4
Grant date fair value per share	$	8.95