On April 9, 2019, the Board of Directors authorized a stock repurchase program to acquire up to $15.0 million of its common stock. Any repurchases under the program will be made from time to time on the open market at prevailing market prices. On April 1, 2021, the Company’s Board of Directors approved an extension and expansion of this repurchase program to acquire up to $25 million of its common shares, expiring April 9, 2023. On March 3, 2023, the Company’s Board of Directors approved a two-year extension of the stock repurchase plan. As of December 31, 2023, the Company has repurchased 0.6 million shares of its common stock for a total cost of $8.4 million.

On October 30, 2013, the Board of Directors adopted, and on December 27, 2013, the stockholders approved, the 2013 Stock-Based Incentive Compensation Plan (the “2013 Plan”), which was subsequently amended at the 2019 annual meeting of stockholders and at the 2021 annual meeting of stockholders to increase the total number of shares of common stock authorized for grant. The Company’s stock-based compensation program is a broad-based program designed to attract and retain employees while also aligning employees’ interests with the interests of the Company's stockholders. In addition, members of the Board of Directors participate in the stock-based compensation program in connection with their service on the board.

Stock option awards outstanding under the 2013 Plan are time-based and granted at exercise prices which are equal to the market value of the Company’s common stock on the grant date and expire no later than ten years from the date of grant, but only to the extent they have vested. The options generally vest as specified in the option agreements subject, in some instances, to acceleration in certain circumstances. The restrictions on restricted stock generally lapse over a three-year period from the date of the grant. In the event a participant terminates

employment with the Company, any vested stock options, and any restricted stock still subject to restrictions are generally forfeited if they are not exercised within 90 days.

The following table presents the stock activity and the total number of shares available for grant as of December 31, 2023:


	(in thousands)
Balance at December 31, 2022		550
Plan Amendment		1,049
Options cancelled		21
Restricted stock granted		(520	)
Forfeited/ Expired restricted stock added back		28
Performance-Based restricted stock unearned		94
Performance-Based restricted stock granted		(163	)
Balance at December 31, 2023		1,059

Total estimated stock-based compensation expense for employees and non-employees, related to all of the Company's stock-based awards, was comprised as follows:


	Year ended December 31,
	2023		2022		2021
	(in thousands)
Cost of revenue	$	824	$	433	$	343
Selling and marketing		2,475		2,028		1,746
Research and development		1,870		1,444		1,379
General and administrative		6,814		4,079		4,188
Total stock-based compensation	$	11,983	$	7,984	$	7,656

Forfeitures on option grants are estimated at 10% based on evaluation of historical and expected future turnover for non-executives and 0% for executives. Stock-based compensation expense was recorded net of estimated forfeitures, such that expense was recorded only for those stock-based awards that are expected to vest. The Company reviews this assumption periodically and will adjust it if it is not representative of future forfeiture data and trends within employee types (executive vs. non-executive).

On May 1, 2023, the Company announced that the Company and Juergen Stark, Chairman, Chief Executive Officer and President of the Company, agreed that Mr. Stark would not continue as Chairman, Chief Executive Officer and President of the Company, with his employment to terminate effective as of the close of business on June 30, 2023. On May 2, 2023, the Company entered into a separation agreement with Mr. Stark, resulting in an acceleration of the total stock-based compensation associated with equity awards granted to him. During the year ended December 31, 2023, the Company recorded a total of $4.0 million in stock-based compensation expenses and related payroll that would not have been recognized if Mr. Stark had not announced his retirement.

The associated tax benefit recognized on the consolidated statements of operations for the fiscal years ended December 31, 2023, 2022 and 2021 was approximately $0.3 million, $0.2 million and $2.2 million, respectively.


	Options Outstanding
	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)
Outstanding at December 31, 2022		1,577,545		$	7.66		5.81	$	2,465,015
Granted		-			-
Exercised		(515,089	)		4.39
Forfeited		(21,004	)		16.45
Outstanding at December 31, 2023		1,041,452		$	9.10		4.22	$	3,137,285
Vested and expected to vest at December 31, 2023		1,040,873		$	9.22		4.22	$	3,136,393
Exercisable at December 31, 2023		984,120		$	9.23		4.09	$	2,975,342

Aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options. The aggregate intrinsic value of option exercises was $3.3 million, $0.8 million and $13.6 million for the years ended December 31, 2023, 2022 and 2021, respectively.

As of December 31, 2023, total unrecognized compensation cost related to non-vested stock options granted to employees was $0.4 million, which is expected to be recognized over a remaining weighted average vesting period of 0.4 years.

No options were granted during the years ended December 31, 2023 and 2022. The weighted average grant date fair value of options granted during the year ended December 31, 2021 was $14.89. The total estimated fair value of employee options vested during the three years ended December 31, 2023 was $1.0 million, $4.2 million and $2.6 million, respectively.


	Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested restricted stock at December 31, 2022		865,446		$	18.75
Granted		519,533			9.98
Vested		(591,801	)		16.36
Shares forfeited		(28,236	)		15.83
Nonvested restricted stock at December 31, 2023		764,942		$	14.76

As of December 31, 2023, total unrecognized compensation cost related to the nonvested restricted stock awards granted was $8.3 million, which is expected to be recognized over a remaining weighted average vesting period of 2.2 years.

As of December 31, 2023, the Company had 162,672 performance-based restricted share units outstanding. The vesting of performance-based restricted share units is determined over a three-year period based on (i) the amount by which revenue growth exceeds a defined baseline market growth each year and (ii) the achievement of specified tiers of adjusted EBITDA as a percentage of net revenue each year, with the ability to earn and vest into such units ranging from 0% to 200%. Included in the Company’s share-based compensation was expense recognized for the Company’s performance-based restricted share unit awards of $1.7 million in 2023 and $1.0 million in 2021. There was no stock-based compensation expense recorded in 2022 as the performance conditions were not achieved.