Equity Incentive Plans and Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of shares available for grant

A summary of shares available for grant under the Company’s plans is as follows:

	Shares Available  for Grant
Total shares available for grant as of December 31, 2023	11,954,150
Stock options expired	1,125
Nonvested equity stock and stock units granted (1) (2)	(1,058,225)
Nonvested equity stock and stock units forfeited (1)	213,706
Total shares available for grant as of June 30, 2024	11,110,756

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(1)    For purposes of determining the number of shares available for grant under the 2015 Plan against the maximum number of shares authorized, each restricted stock unit granted prior to April 27, 2023 reduces the number of shares available for grant by 1.5 shares and each restricted stock unit forfeited increases shares available for grant by 1.5 shares. Each restricted stock unit granted on or after April 27, 2023 reduces the number of shares available for grant by 1.0 shares and each restricted stock unit forfeited increases shares available for grant by 1.0 shares.

(2)     Amount includes approximately 0.1 million shares that have been reserved for potential future issuance related to certain performance unit awards granted in the second quarter of 2024 and discussed under the section titled “Nonvested Equity Stock and Stock Units” below.

Schedule of stock option activity

The following table summarizes stock option activity under the Company’s equity incentive plans for the six months ended June 30, 2024 and information regarding stock options outstanding, exercisable, and vested and expected to vest as of June 30, 2024.

	Options Outstanding
(In thousands, except shares, per share amounts and years)	Number of  Shares	Weighted-  Average  Exercise Price  Per Share		Weighted-  Average  Remaining  Contractual  Term (years)	Aggregate  Intrinsic  Value
Outstanding as of December 31, 2023	124,732	$	11.60
Options exercised	(25,125)	$	8.76		$	1,256
Options expired	(1,125)	$	8.76
Outstanding and vested as of June 30, 2024	98,482	$	12.36	3.72	$	4,570

Schedule of nonvested equity stock and stock units activity

The following table reflects the activity related to nonvested equity stock and stock units for the six months ended June 30, 2024:

Nonvested Equity Stock and Stock Units	Shares	Weighted-  Average  Grant-Date  Fair Value
Nonvested at December 31, 2023	3,430,192	$	32.90
Granted	913,543	$	63.98
Vested	(1,128,550)	$	24.64
Forfeited	(149,962)	$	35.47
Nonvested at June 30, 2024	3,065,223	$	43.45