Stock compensation (Tables)

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of valuation assumptions used for valuation of fair value of stock compensation granted

We utilized the Black-Scholes valuation model for estimating the fair value of the stock compensation granted, with the following weighted-average assumptions:


	Employee Stock Options												Employee Stock Purchase Plan
	For the Three Months Ended						For the Six Months Ended						For the Three Months Ended						For the Six Months Ended
	June 30,												June 30,
	2023			2022			2023			2022			2023			2022			2023			2022
Average risk-free interest rates	3.88		%	3.04		%	3.76		%	1.67		%	4.87		%	2.92		%	4.27		%	2.77		%
Average expected life (in years)	5.58			5.51			4.95			4.77			0.50			0.50			0.50			0.50
Volatility	29		%	33		%	32		%	37		%	27		%	39		%	23		%	28		%
Weighted-average fair value (in dollars)	$	22.57		$	26.35		$	26.78		$	25.30		$	13.82		$	14.91		$	14.08		$	14.53

Schedule of option activity under the 2010 Stock Plan

Option activity under our 2010 Stock Incentive Plan (the “2010 Stock Plan”) was as follows:


	Shares Subject to Outstanding Options
	Shares	Weighted Average Exercise Price
Balance at December 31, 2022	12,650,359	$	87.25
Options granted	702,470	$	78.53
Options exercised	(231,417)	$	67.05
Options cancelled	(755,507)	$	94.07
Balance at June 30, 2023	12,365,905	$	86.72

Schedule of RSU award and PSU activity under the 2010 Stock Plan

Restricted stock unit (“RSU”) and performance share (“PSU”) award activity under the 2010 Stock Plan was as follows:


	Shares Subject to Outstanding Awards
	Shares	Grant Date Value
Balance at December 31, 2022	5,187,592	$	81.24
RSUs granted	829,206	$	77.15

RSUs released	(186,167)	$	77.96

RSUs cancelled	(125,325)	$	80.67
PSUs cancelled	(971)	$	106.47
Balance at June 30, 2023	5,704,335	$	80.77

Summary of shares available for grant

The following table summarizes our shares available for grant under the 2010 Stock Plan. Each RSU and PSU grant reduces the available share pool by 2 shares.


			Shares Available for Grant
Balance at December 31, 2022			5,056,370
Additional authorization			12,500,000
Options, RSUs and PSUs granted			(2,360,882)
Options, RSUs and PSUs cancelled			1,006,844
Balance at June 30, 2023			16,202,332