Prior to May 10, 2022, the Company granted RSUs to employees and directors under the 2014 Stock Incentive Plan (the "2014 Plan"). Following shareholder approval of the 2022 Stock Incentive Plan (the "2022 Plan" and, together with the 2014 Plan, the "Plans") on May 10, 2022, the Company discontinued granting RSUs to employees and directors under the 2014 Plan and began granting them under the 2022 Plan. The Plans are administered by the Compensation Committee of the Company's Board of Directors. The Plans are intended to attract and retain employees and directors, and to provide an incentive for these individuals to assist the Company to achieve long-range performance goals and enable these individuals to participate in the long-term growth of the Company.

The total stock-based compensation expense included in the Company's condensed consolidated statements of operations and comprehensive income was as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Cost of revenues	$	2	$	1	$	3	$	2
Research and development		2		1		3		2
Selling, general and administrative		9		7		15		15
Total pre-tax stock-based compensation expense	$	13	$	9	$	21	$	19

At June 30, 2022, the total compensation expense related to unvested stock-based awards granted to employees and directors under the Plans that had not been recognized was $54. The Company determines the fair value of RSUs based on the closing market price of the Company's common stock on the date of the award and estimates the fair value of employee stock purchase plan rights using the Black-Scholes valuation model. Such values are recognized as expense on a straight-line basis for time-based awards and using the accelerated graded vesting method for performance-based awards, both over the requisite service periods.

The following table presents the activity for RSUs under the Plans:


	Six Months Ended June 30, 2022
	Outstanding RSUs			Weighted Average Grant Date Fair Value Per Share
RSUs – beginning of period		0.5		$	127.93
Granted		0.4		$	113.14
Vested		(0.2	)	$	119.15
RSUs – end of period		0.7		$	122.15

The Company had an immaterial amount of stock appreciation rights outstanding as of June 30, 2022 and December 31, 2021.