Stock-Based Compensation Expense

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

NOTE 11 – STOCK-BASED COMPENSATION EXPENSE

The effect of recording stock-based compensation (“SBC”) expense for the three and six months ended June 30, 2024 and 2023 is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	1,093	$	736		1,902		1,330
Selling, general and administrative		5,499		3,820		9,835		6,866
Total stock-based compensation expense	$	6,592	$	4,556	$	11,737	$	8,196

There were no options granted during the three and six months ended June 30, 2024 and 2023.

The Company uses a Monte Carlo simulation to determine the grant date fair value of performance stock awards subject to market conditions, or market-based PSUs. The following assumptions were used to value the restricted stock units subject to market conditions granted during the six months ended June 30, 2024 and 2023:


	May 2024			May 2023			March 2023
Expected life (years)		3.0			3.0			3.0
Risk-free interest rate		4.5	%		3.6	%		4.5	%
Dividend yield		1.8	%		2.3	%		1.9	%
Expected volatility		57.0	%		63.3	%		68.5	%

Grants under the 2020 ESPP occur in June and December, as discussed in “Note 10 – Stockholders’ Equity”. The following assumptions were used to value the shares for these grants.


	June 2024			June 2023
Expected life (years)		2.0			2.0
Risk-free interest rate		4.8	%		4.3	%
Dividend yield		1.7	%		2.0	%
Expected volatility		57.0	%		63.5	%