Stock-based Compensation Plans (Tables)

12 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation Expenses

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

Stock Option Fair Value Assumptions and Weighted Average Fair Value of Stock Options Granted

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

Schedule of Stock Option Activity

Stock option activity was as follows:

(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

Schedule of Restricted Stock Activity

Restricted Stock activity was as follows:

(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