The Company has stock-based compensation plans under which it grants stock options, restricted stock awards, restricted stock units and deferred stock units. Stock-based compensation expense was reported as follows on the consolidated statements of operations:

	Fiscal Year
(In thousands)	2021		2020		2019
Product costs	$	122	$	119	$	135
Research and development		1,298		896		876
Selling, general and administrative		4,443		4,438		4,066
Total stock-based compensation expense	$	5,863	$	5,453	$	5,077

As of September 30, 2021, approximately $8.4 million of total unrecognized compensation costs related to non-vested awards is expected to be recognized over a weighted average period of approximately 2.2 years.

Under the 2019 Equity Incentive Plan (“2019 Plan”), the Company is authorized to issue 1,100,000 shares, plus the number of shares pursuant to any awards granted under the 2009 Equity Incentive Plan (“2009 Plan”) that were outstanding on the effective date of the 2019 Plan that expire, are cancelled or forfeited, or are settled for cash. As of September 30, 2021, there were approximately 485,000 shares available for future equity awards under the 2019 Plan, including stock options, restricted stock, restricted stock units, and deferred stock units.

The Company grants non-qualified stock options at fair market value on the grant date to certain key employees and members of the Board. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options as of the date of each grant. Stock option fair value assumptions and the weighted average fair value of stock options granted were as follows:

	Fiscal Year
	2021			2020			2019
Stock option fair value assumptions:
Risk-free interest rates		0.40	%		1.41	%		2.75	%
Expected life (years)	4.6			4.6			4.5
Expected volatility		43	%		39	%		34	%
Dividend yield		—	%		—	%		—	%
Weighted average grant date fair value of stock options granted	$	14.71		$	14.13		$	17.89

The risk-free interest rate assumption is based on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the awards. The expected life of options granted is determined based on the Company’s experience. Expected volatility is based on the Company’s stock price movement over a period approximating the expected term. Based on management’s judgment, dividend yields are expected to be zero for the expected life of the options.

With respect to members of the Board, non-qualified stock options generally become exercisable on a monthly pro-rata basis within the one-year period following the date of grant. With respect to employees, non-qualified stock options generally become exercisable at a 25% rate on each of the first four anniversaries following the grant date. Non-qualified stock options generally expire in seven years or upon, or shortly after, termination of employment or service as a Board member. The stock-based compensation table above includes stock option expenses recognized related to these awards, which totaled $2.8 million, $2.5 million and $2.2 million in fiscal 2021, 2020 and 2019, respectively.

As of September 30, 2021, the aggregate intrinsic value of the option shares outstanding and option shares exercisable was $15.1 million and $7.9 million, respectively. As of September 30, 2021, the weighted average remaining contractual life of options outstanding and options exercisable was 4.6 years and 3.4 years, respectively. The total pre-tax intrinsic value of options exercised was $7.1 million, $2.0 million and $0.3 million in fiscal 2021, 2020 and 2019, respectively. The intrinsic value represents the difference between the exercise price and the fair market value of the Company’s common stock on the last day of the respective fiscal year end.

(In thousands, except per share data)	Number of Shares			Weighted Average Exercise Price
Options outstanding at September 30, 2018		711		$	26.28
Granted		179			55.09
Exercised		(13	)		22.03
Forfeited and expired		(6	)		42.28
Options outstanding at September 30, 2019		871			32.18
Granted		299			41.06
Exercised		(125	)		22.89
Forfeited and expired		(105	)		41.69
Options outstanding at September 30, 2020		940			35.18
Granted		274			40.95
Exercised		(248	)		24.22
Forfeited and expired		(44	)		44.58
Options outstanding at September 30, 2021		922			39.39
Options vested and exercisable at September 30, 2021		402		$	36.07

The Company has entered into restricted stock agreements with certain key employees, covering the issuance of common stock (“Restricted Stock”). Restricted Stock generally vests at a 33% rate on each of the first three anniversaries following the grant date. Restricted Stock is released to employees if they are employed by the Company at the end of the vesting period. Restricted Stock is valued based on the market value of the shares as of the date of grant with the value allocated to expense evenly over the vesting period. The stock-based compensation table above includes Restricted Stock expenses recognized related to these awards, which totaled $2.2 million, $2.0 million and $1.7 million in fiscal 2021, 2020 and 2019, respectively.

(In thousands, except per share data)	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock awards at September 30, 2018		85		$	30.30
Granted		45			56.05
Vested		(39	)		28.61
Forfeited		(1	)		47.86
Unvested restricted stock awards at September 30, 2019		90			43.69
Granted		67			41.40
Vested		(43	)		38.74
Forfeited		(14	)		44.76
Unvested restricted stock awards at September 30, 2020		100			44.16
Granted		71			38.83
Vested		(48	)		44.07
Forfeited		(4	)		40.45
Unvested restricted stock awards at September 30, 2021		119		$	41.14

The Company has entered into restricted stock unit agreements with certain key employees in foreign jurisdictions and members of the Board, covering the issuance of common stock (“RSUs”). With respect to employees, RSUs generally vest at a 33% rate on each of the first three anniversaries following the grant date, and RSUs are settled in shares and issued to the employees if they are employed by the Company at the end of the vesting period. With respect to members of the Board, RSUs vest on a monthly pro-rata basis within the one-year period following the date of grant, and RSUs are settled in shares and generally issued upon termination of service as a Board member. RSUs are valued based on the market value of the shares as of the date of grant with the value allocated to expense evenly over the vesting period. The Company awarded approximately 17,000, 18,000 and 12,000 RSUs in fiscal 2021, 2020 and 2019, respectively. As of September 30, 2021 and 2020, outstanding RSUs (including unvested units and vested units not yet settled) totaled approximately 61,000 and 65,000 units, respectively, with a weighted average grant date fair value per unit of $33.45 and $31.12, respectively. The stock-based compensation table above includes RSU expenses recognized related to these awards, which totaled $0.5 million, $0.6 million and $0.6 million in fiscal 2021, 2020 and 2019, respectively.

Directors may elect to receive their annual fees for services to the Board in deferred stock units (“DSUs”). DSUs are fully vested and expensed upon grant at the market value of the shares on the grant date. DSUs are settled in shares and issued to the Director upon termination of service as a Board member. As of September 30, 2021 and 2020, outstanding, fully vested DSUs totaled approximately 34,000 and 33,000 units, respectively, with a weighted average grant date fair value per unit of $30.32 and $28.41, respectively. The stock-based compensation table above includes DSU expenses recognized related to these awards, which totaled $0.1 million per year in each of fiscal 2021, 2020 and 2019.

In fiscal 2017 and prior years, the Company entered into performance share agreements with certain key employees covering the issuance of common stock (“Performance Shares”). The Organization and Compensation Committee of the Board of Directors (the “Committee”) established cumulative revenue and cumulative earnings before interest, income taxes, depreciation and amortization (“EBITDA”) for the applicable three-year performance period as the performance objectives for the fiscal 2017 and 2016 awards. The fiscal 2017 and 2016 awards also included performance objectives related to achievement of the Company’s strategic initiatives. The fair value of the Performance Shares, at target, was $1.2 million for the grant awarded in fiscal 2017. The stock-based compensation table above includes Performance Share expenses recognized related to these awards, which totaled zero, less than $0.1 million and $0.4 million in fiscal 2021, 2020 and 2019, respectively.

Under the amended 1999 Employee Stock Purchase Plan (“ESPP”), the Company is authorized to issue up to 600,000 shares of common stock. All full-time and part-time U.S. employees can elect to have up to 10% of their annual compensation withheld, with an annual limit of $25,000, to purchase the Company’s common stock at purchase prices defined within the provisions of the ESPP. ESPP share awards are valued based on the value of the discount feature plus the fair value of the optional features as of the date of grant using the Black-Scholes valuation model. The value of these share awards is allocated to expense evenly over each six-month purchase period. Employee contributions to the ESPP included in accrued liabilities on the consolidated balance sheets totaled $0.1 million as of both September 30, 2021 and 2020. The stock-based compensation table above includes expenses recognized related to the ESPP, which totaled $0.2 million, $0.2 million and $0.1 million for fiscal 2021, 2020 and 2019, respectively.