STOCK PLANS AND SHARE BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2023

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Stock-based Compensation Expense

The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
(In thousands)	2023		2022		2021
Cost of revenues	$	1,692	$	1,132	$	2,359
Research and development		10,939		10,428		12,127
Sales and marketing		6,888		6,035		7,630
General and administrative		9,009		4,769		15,493
Total stock-based compensation expense	$	28,528	$	22,364	$	37,609

Share-based Payment Arrangement, Nonvested Award, Cost

The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted average period over which it is expected to be recognized as of December 31, 2023:

	Unrecognized Compensation		Weighted Average
	Expense for Unvested		Remaining Recognition
	Awards		Period
	(In thousands)		(In years)
Long-term performance-based awards	$	—	—
Restricted stock units		46,856	2.66
Purchase plan		155	0.08
Total unrecognized compensation expense	$	47,011

Fair value assumptions for employees' stock purchase rights under the Purchase Plan

The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions used during the three years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
	2023			2022			2021
Risk-free interest rates		5.15	%		1.71	%		0.07	%
Expected volatility rates		37	%		41	%		41	%
Expected dividend yield		0.90	%		0.89	%		0.57	%
Expected term of purchase rights (in years)		0.49			0.50			0.50
Weighted-average estimated fair value of purchase rights	$	23.75		$	21.63		$	23.92

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of RSU awards outstanding as of December 31, 2023, and activity during the three years then ended, is presented below:

				Weighted-Average	Aggregate
		Weighted-Average		Remaining	Intrinsic
	Shares	Grant Date Fair		Contractual Term	Value
	(In thousands)	Value Per Share		(In years)	(In thousands)
Outstanding at January 1, 2021	1,518	$	35.51
Granted	271	$	83.79
Vested	(546)	$	35.03
Forfeited	(99)	$	39.85
Outstanding at December 31, 2021	1,144	$	46.81
Granted	519	$	76.01
Vested	(481)	$	44.70
Forfeited	(86)	$	60.02
Outstanding at December 31, 2022	1,096	$	60.52
Granted	335	$	80.97
Vested	(418)	$	53.08
Forfeited	(32)	$	73.29
Outstanding at December 31, 2023	981	$	70.27	1.48	$	80,585
Outstanding and expected to vest at December 31, 2023	918			1.39	$	75,384

Performance Based Awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of performance-based awards outstanding

A summary of PSU awards outstanding as of December 31, 2023, and activity during the three years then ended, is presented below:

				Weighted-
				Average
		Weighted-Average		Remaining	Aggregate
	Shares	Grant Date Fair		Contractual Term	Intrinsic Value
	(In thousands)	Value Per Share		(In years)	(In thousands)
Outstanding at January 1, 2021	150	$	46.27
Granted	105	$	84.48
Vested	(150)	$	46.27
Forfeited or canceled	(1)	$	85.01
Outstanding at December 31, 2021	104	$	84.47
Granted	119	$	79.91
Vested	(104)	$	84.48
Forfeited or canceled	(85)	$	79.89
Outstanding at December 31, 2022	34	$	79.94
Granted	131	$	82.96
Vested	(34)	$	79.94
Forfeited or canceled	(93)	$	82.96
Outstanding at December 31, 2023	38	$	82.95	—	$	3,131
Outstanding and expected to vest at December 31, 2023	38			—	$	3,131

Long-Term Performance-Based Awards (PRSUs)

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of performance-based awards outstanding

A summary of PRSU awards outstanding as of December 31, 2023, and activity during the three years then ended, is presented below:

				Weighted-Average	Aggregate
		Weighted-Average		Remaining	Intrinsic
	Shares	Grant Date Fair		Contractual Term	Value
	(In thousands)	Value Per Share		(In years)	(In thousands)
Outstanding at January 1, 2021	301	$	41.90
Granted	103	$	82.92
Vested	(6)	$	29.94
Forfeited or canceled	(15)	$	40.05
Outstanding at December 31, 2021	383	$	53.14
Granted	110	$	78.96
Vested	(135)	$	34.09
Forfeited or canceled	(122)	$	49.68
Outstanding at December 31, 2022	236	$	77.82
Granted	146	$	80.92
Vested	(23)	$	49.68
Forfeited or canceled	(103)	$	82.92
Outstanding at December 31, 2023	256	$	80.08	1.57	$	20,987
Outstanding and expected to vest at December 31, 2023	—			—	$	—