Stock-based compensation expense for each employee and director is presented in the same statement of operations caption as their cash compensation. Stock-based compensation expense by statement of operations caption and the related income tax benefit were as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
(In thousands)	2022		2021		2022		2021
Cost of sales	$	38	$	39	$	117	$	116
Research and development expenses	326		321		1,004		952
Selling, general and administrative expenses:
Employees	1,842		1,712		5,421		5,285
Outside directors	233		400		1,033		1,163
Total employee and director stock-based compensation expense	$	2,439	$	2,472	$	7,575	$	7,516
Income tax benefit	$	397	$	420	$	1,265	$	1,302


	Number of Options (in thousands)	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021	800	$	45.55
Granted	140	33.42
Exercised	—	—			$	—
Forfeited/canceled/expired	(74)	65.54
Outstanding at September 30, 2022 (1)	866	$	41.89	3.38	$	34
Vested and expected to vest at September 30, 2022 (1)	866	$	41.89	3.38	$	34
Exercisable at September 30, 2022 (1)	662	$	42.39	2.46	$	34

(1)The aggregate intrinsic value represents the total pre-tax value (the difference between our closing stock price on the last trading day of the third quarter of 2022 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had they all exercised their options on September 30, 2022. This amount will change based on the fair market value of our stock.

The assumptions we utilized in the Black-Scholes option pricing model and the resulting weighted average fair value of stock option grants were the following:


	Three Months Ended September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
Weighted average fair value of grants	$	12.38		$	—		$	14.51		$	23.97
Risk-free interest rate	2.82		%	—		%	1.93		%	0.41		%
Expected volatility	48.92		%	—		%	49.35		%	48.49		%
Expected life in years	5.19			0.00			4.73			4.62

As of September 30, 2022, we expect to recognize $2.8 million of total unrecognized pre-tax stock-based compensation expense related to non-vested stock options over a remaining weighted-average life of 1.9 years.


	Shares (in thousands)		Weighted-Average Grant Date Fair Value
Non-vested at December 31, 2021	$	310	$	44.41
Granted	262		31.05
Vested	(176)		41.32
Forfeited	(5)		43.22
Non-vested at September 30, 2022	$	391	$	36.88

As of September 30, 2022, we expect to recognize $10.7 million of total unrecognized pre-tax stock-based compensation expense related to non-vested restricted stock awards over a weighted-average life of 1.8 years.