Stock-Based Compensation Plans (Tables)

12 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expenses

The Company’s stock-based compensation expenses for the years ended September 30 were allocated to the following expense categories

	2018		2017		2016
Product costs	$	69	$	90	$	22
Research and development		801		510		324
Selling, general and administrative		3,937		2,872		3,498
Total stock-based compensation expense	$	4,807	$	3,472	$	3,844

Assumptions Used in Stock Option Plans

The assumptions used as inputs in the model for the years ended September 30 were as follows:

	2018			2017			2016
Risk-free interest rates		2.18	%		1.74	%		1.89	%
Expected life	4.8 years			4.6 years			4.6 years
Expected volatility		33	%		34	%		37	%
Dividend yield		0	%		0	%		0	%

Schedule of Stock Option Activity

The following table summarizes all stock options activity and stock options outstanding and exercisable under the stock option plans during fiscal 2018, 2017 and 2016:

	Number of Shares			Weighted Average Exercise Price
Outstanding at September 30, 2015		1,118,008		$	20.10
Granted		241,582			20.63
Exercised		(437,850	)		15.68
Forfeited and expired		(94,415	)		31.52
Outstanding at September 30, 2016		827,325			21.30
Granted		229,039			24.08
Exercised		(6,819	)		13.89
Forfeited and expired		(47,640	)		30.65
Outstanding at September 30, 2017		1,001,905			21.54
Granted		269,961			34.08
Exercised		(450,495	)		19.46
Forfeited and expired		(110,825	)		30.18
Outstanding at September 30, 2018		710,546			26.28
Exercisable at September 30, 2018		236,302		$	22.33

Schedule of Restricted Stock Awards Activity

The following table summarizes all restricted stock awards activity during fiscal 2018, 2017 and 2016:

	Number of Shares			Weighted Average Grant Price
Balance at September 30, 2015		27,775		$	22.12
Granted		20,108			20.14
Vested		(12,311	)		22.19
Forfeited		(2,439	)		21.17
Balance at September 30, 2016		33,133			20.96
Granted		51,559			25.12
Vested		(14,497	)		21.10
Forfeited		(2,278	)		25.12
Balance at September 30, 2017		67,917			23.98
Granted		56,244			34.38
Vested		(28,717	)		23.78
Forfeited		(10,020	)		29.10
Balance at September 30, 2018		85,424		$	30.30

Schedule of Fair Value at the Date of Grant

The aggregate number of shares that could be awarded to key employees if the minimum, target and maximum performance goals are met, based upon the fair value at the date of grant is as follows:

Performance Period	Minimum Shares		Target Shares		Maximum Shares
Fiscal 2016 - 2018		11,910		59,548		119,096
Fiscal 2017 - 2019		9,352		46,758		93,516