The Company’s stock-based compensation is in accordance with the Company's amended 2015 Incentive Compensation Plan (the “Plan”), pursuant to which the Compensation Committee of the Company is authorized to grant up to 13,650,000 shares to officers and employees of the Company, in the form of equity-based awards, including time or performance based options and restricted stock. In addition, the Company may grant cash-settled awards, including stock-appreciation rights (SARs) and phantom stock awards. As of December 31, 2022, there were 5,037,128 shares available for grant under the Plan.

In June 2019, the Company's shareholders approved the 2019 Employee Stock Purchase Plan (the "ESPP"), which was effective July 1, 2019. In August 2021, the number of shares reserved for issuance under the ESPP was increased to 1.25 million shares. The ESPP allows eligible employees to purchase shares of common stock at a discount of up to 15% through payroll deductions of their eligible compensation, subject to any plan limitations. The ESPP provides for six-month offering periods beginning January 1 and July 1 of each year, and each offering period consists of a six-month purchase period. On each purchase date, eligible employees may purchase the Company's common stock at a price per share equal to 85% of the lesser of (1) the fair

market value of the common stock on the offering date or (2) the fair market value of the common stock on the purchase date. As of December 31, 2022, 670,306 shares had been issued under the ESPP.

Stock compensation expense for the years ended December 31, 2022, 2021 and 2020 for equity and liability-classified awards was $4.6 million, $3.2 million and $3.6 million respectively.

The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations for the years ended December 31, 2022, 2021 and 2020:


	Year Ended December 31,
(in thousands)	2022	2021	2020
Cost of sales	$65	$32	$95
Selling, general and administrative expenses	4,253	2,896	3,192
Research and development expenses	302	285	311
Total	$4,620	$3,213	$3,598

During the years ended December 31, 2022 and 2021, the compensation and talent committee of the Company's board of directors (the "Compensation Committee") approved time-based stock options ("Options") to be granted to new officers and certain employees of the Company, which vest ratably over three years. No Options were granted during the year ended December 31, 2020. A summary of the status of the Company’s Options for the years ended December 31, 2022 and 2021 were as follows:


(in thousands)	Number of Share Underlying Awards	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Term (years)
Outstanding at December 31, 2020	800	$6.47	6.67
Granted	1,098	1.52	9.48
Exercised	—	—	0.00
Forfeited or expired	(398)	4.91	5.98
Outstanding at December 31, 2021	1,500	3.62	8.34
Exercisable at December 31, 2021	360	8.56	5.15
Vested and expected to vest at December 31, 2021	1,500	3.62	8.34

Outstanding at Outstanding at December 31, 2021	1,500	3.62	8.34
Granted	55	1.69	9.39
Exercised	(339)	2.01	8.42
Forfeited or expired	—	—	0.00
Outstanding at December 31, 2022	1,216	3.98	7.13
Exercisable at December 31, 2022	429	7.64	4.63
Vested and expected to vest at December 31, 2022	1,216	$3.98	7.13

The fair value of each Option was estimated on the date of grant using the Hull-White or Black-Scholes option pricing models with the assumptions described below. For the periods indicated, since the Company has limited historical volatility information available, the expected volatility was based on actual volatility for comparable public companies projected over the expected terms of Options and the actual volatility for the Company since July 1, 2015. The Company records forfeitures as they occur. The risk-free interest rate was based on the U.S. Treasury yield curve at the time of the grant over the expected term of the Options. The expected life for the Hull-White model was calculated as the average time to achieve the 2.0x strike exercise price in the simulation. The expected life for the Black-Scholes model was estimated using the simplified method.


	2022
Weighted average grant date fair value	$2.00
Risk-free interest rate	0.9	%	—	3.6%
Expected life (years)	5.83
Estimated volatility factor	53.6	%	—	78.1%
Expected dividends	None

During the year ended December 31, 2019, the Compensation Committee approved time-based stock appreciation rights ("SARs") to be granted to employees of the Company outside of the United States, which vest ratably over three years. No SARs were granted during the years ended December 31, 2022, and 2021. A summary of the Company’s SARs as of December 31, 2022 and 2021 were as follows:


(in thousands)	Number of Awards	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Term (years)
Outstanding at December 31, 2020	48	$12.00	4.69
Granted	—	—	0.00
Exercised	—	—	0.00
Forfeited or expired	—	—	0.00
Outstanding at December 31, 2021	48	12.00	3.69
Exercisable at December 31, 2021	48	12.00	3.69
Vested and expected to vest at December 31, 2021	48	12.00	3.69

Outstanding at December 31, 2021	48	12.00	3.69
Granted	—	—	0.00
Exercised	—	—	0.00
Forfeited or expired	(7)	12.00	2.68
Outstanding at December 31, 2022	41	12.00	2.70
Exercisable at December 31, 2022	41	12.00	2.70
Vested and expected to vest at December 31, 2022	41	$12.00	2.70

Holders of these SARs are entitled under the terms of the Plan to receive cash payments calculated based on the excess of the Company’s stock price over the target price in their award; consequently, these awards are accounted for as liability-type awards, and the Company measures compensation cost based on their estimated fair value at each reporting date and the number of options expected to vest.

Upon issuance, the fair value of each SAR award was estimated using the Hull-White option pricing model with the assumptions described below. For the periods indicated, since the Company has limited historical volatility information available, the expected volatility was based on actual volatility for comparable public companies projected over the expected terms of SAR awards. The Company records forfeitures as they occur. The risk-free interest rate was based on the U.S. Treasury yield curve at the time of the grant over the expected term of the SAR awards. The expected life was calculated as the average time to achieve the 2.0x strike exercise price in the simulation. SARs are liability classified within Accrued expenses and other current liabilities and they are revalued at each reporting date. The assumptions used to value the SARs as of December 31, 2022 and 2021 are presented below:

During the years ended December 31, 2022 and 2021, the Compensation Committee approved equity-classified performance-based restricted stock units (RSUs) and time-based restricted stock and RSUs to be granted to officers and employees of the Company, which vest ratably over three years. A summary of the Company’s RSUs and restricted stock as of December 31, 2022 and 2021 were as follows:


(in thousands)	Number of Shares	Weighted-Average Grant Date Fair Value
Non-vested Restricted Stock & RSUs at December 31, 2020	2,454	$2.12
Granted	2,143	2.07
Vested	(525)	2.69
Forfeited or expired	(1,045)	1.95
Non-vested Restricted Stock & RSUs at December 31, 2021	3,027	2.05

Non-vested Restricted Stock & RSUs at December 31, 2021	3,027	2.05
Granted	2,429	1.88
Vested	(1,694)	1.92
Forfeited or expired	(315)	2.62
Non-vested Restricted Stock and RSUs at December 31, 2022	3,447	$1.94

Unrecognized compensation expense for performance-based restricted stock and time-based restricted stock and RSU is $4.1 million, which is expected to be recognized over a weighted average period of 1.8 years.

During the years ended December 31, 2022 and 2021, the Compensation Committee approved phantom stock awards to be awarded to employees and one director of the Company located outside of the United States. Phantom stock awarded to employees vest ratably over three years. Phantom stock awarded to the director vest in one year. These awards will be settled in cash upon vesting and are therefore liability-classified within Accrued expenses and other current liabilities, requiring re-measurement at each balance sheet date. A summary of the Company’s Phantom Stock Awards as of December 31, 2022 and 2021 were as follows:


(in thousands)	Number of Awards	Weighted-Average Grant Date Fair Value
Non-vested phantom stock awards at December 31, 2020	326	$2.26
Granted	68	2.03
Vested	(87)	2.80
Forfeited or expired	(41)	2.17
Non-vested phantom stock awards at December 31, 2021	266	$2.04

Non-vested phantom stock awards at December 31, 2021	266	$2.04
Granted	96	1.86
Vested	(89)	2.10
Forfeited or expired	(54)	2.53
Non-vested phantom stock awards at December 31, 2022	219	$1.82

Certain directors receive shares of restricted stock subject to the terms, provisions and restrictions of the 2015 Incentive Compensation Plan. The shares granted during the year ended December 31, 2022 and 2021, vest over a one-year period on the one year anniversary of each holder's grant date, provided the Director is still serving as a director of the Company. Upon termination of directorship for any reason, the Director immediately forfeits any unvested shares without payment. A summary of the Company’s time-based restricted stock awarded to the board of directors for the years ended December 31, 2022 and 2021 were as follows:


(thousands)	Number of Shares	Weighted-Average Grant Date Fair Value
Non-vested time-based restricted stock at December 31, 2020	187	$2.48
Granted	275	1.96
Vested	(157)	2.48
Forfeited or expired	(30)	2.48
Non-vested time-based restricted stock at December 31, 2021	275	$1.96

Non-vested time-based restricted stock at December 31, 2021	275	$1.96
Granted	343	1.85
Vested	(275)	1.96
Forfeited or expired	—	—
Non-vested time-based restricted stock at December 31, 2022	343	$1.85

As of December 31, 2022, the Company had unrecognized compensation costs for the Director shares of $0.4 million that is expected to be recognized over an average period of 0.6 years.