-Based Compensation

At March 31, 2018, we had four active stock-based compensation plans: the Nonemployee Directors’ Stock Retirement Plan (“Directors’ Plan”), the 2004 Omnibus Long-Term Incentive Plan (“2004 Plan”), the 2009 Omnibus Equity and Performance Incentive Plan (“2009 Plan”), and the 2014 Performance & Incentive Plan (“2014 Plan”). Future grants can only be made under the 2014 Plan.

The following table summarizes the compensation expense included in selling, general and administrative expenses in the Condensed Consolidated Statements of Earnings related to stock-based compensation plans:



	Three Months Ended
	March 31,			March 31,
	2018			2017
Service-Based RSUs	$	455		$	550
Performance-Based RSUs	510			384
Cash-settled RSUs	(42		)	(54		)
Total	$	923		$	880
Income tax benefit	209			331
Net	$	714		$	549

The following table summarizes the unrecognized compensation expense related to non-vested RSUs by type and the weighted-average period in which the expense is to be recognized:



	Unrecognized
	Compensation		Weighted-
	Expense at		Average
	March 31, 2018		Period
Service-Based RSUs	$	2,496	1.93
Performance-Based RSUs	3,874		1.89
Total	$	6,370	1.91

We recognize expense on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award was, in substance, multiple awards.

The following table summarizes the status of these plans as of March 31, 2018:



	2014 Plan	2009 Plan	2004 Plan	Directors' Plan
Awards originally available	1,500,000	3,400,000	6,500,000	N/A
Performance-based options outstanding	295,000	—	—	—
Maximum potential RSU and cash settled awards outstanding	745,978	122,600	57,391	9,620
Maximum potential awards outstanding	1,040,978	122,600	57,391	9,620
RSUs and cash settled awards vested and released	315,792	—	—	—
Awards available for grant	143,230	—	—	—

Stock Options

We have no stock options exercisable or outstanding as of March 31, 2018, other than the performance-based stock options described below.

Performance-Based Stock Options

During 2015 and 2016, the Compensation Committee of the Board of Directors of the Company (the “Committee”) granted a total of 350,000 performance-based stock option awards (“Performance-Based Option Awards”) for certain employees under the 2014 Plan, of which 295,000 remain outstanding after considering forfeitures. The Performance-Based Option Awards have an exercise price of $18.37, a term of five years, and generally will become exercisable (provided the optionee remains employed by the Company or an affiliate) upon our attainment of at least $600,000 in revenues during any of our trailing four quarterly periods (as determined by the Committee) during the term. We have not recognized any expense on these Performance-Based Option Awards for the three-month periods ended March 31, 2018 and 2017, since the revenue target was not deemed likely to be attained based on our current forecast.

Service-Based Restricted Stock Units

The following table summarizes the service-based RSU activity as of and for the three months ended March 31, 2018:



	Units		Weighted Average Grant Date Fair Value
Outstanding at January 1, 2018	399,347		$	14.60
Granted	71,722		26.20
Vested and released	(60,797	)	16.43
Forfeited	(515	)	14.83
Outstanding at March 31, 2018	409,757		$	16.36
Releasable at March 31, 2018	260,478		$	12.48

Performance and Market-Based Restricted Stock Units

The following table summarizes the performance and market-based RSU activity as of and for the three months ended March 31, 2018:



	Units		Weighted Average Grant Date Fair Value
Outstanding at January 1, 2018	271,305		$	18.77
Granted	72,043		28.75
Attained by performance	18,600		17.66
Released	(72,456	)	18.66
Forfeited	(21,700	)	17.66
Outstanding at March 31, 2018	267,792		$	21.44
Releasable at March 31, 2018	—		$	—

The following table summarizes each grant of performance awards outstanding at March 31, 2018.



Description	Grant Date	Vesting Year	Vesting Dependency	Target Units Outstanding	Maximum Number of Units to be Granted
2016 - 2018 Performance RSUs	February 16, 2016	2018	35% RTSR, 35% sales growth, 30% cash flow	92,840	185,680
2017 - 2019 Performance RSUs	February 9, 2017	2019	35% RTSR, 35% sales growth, 30% cash flow	71,796	143,592
2017 - 2019 Performance RSUs	February 9, 2017	2018 - 2020	Operating Income	27,113	27,113
2018 - 2020 Performance RSUs	February 8, 2018	2020	35% RTSR, 35% sales growth, 30% cash flow	40,223	80,446
2018 - 2020 Performance RSUs	February 16, 2018	2020	35% RTSR, 35% sales growth, 30% cash flow	31,820	63,640
Single Crystal Performance RSUs	March 31, 2016	2018	Various	4,000	8,000

Cash-Settled Restricted Stock Units

Cash-Settled RSUs entitle the holder to receive the cash equivalent of one share of common stock for each unit when the unit vests. These RSUs are issued to key employees residing in foreign locations as direct compensation. Generally, these RSUs vest over a three-year period. Cash-Settled RSUs are classified as liabilities and are remeasured at each reporting date until settled. At March 31, 2018 and December 31, 2017 we had 17,361 and 14,082 cash-settled RSUs outstanding, respectively. At March 31, 2018 and December 31, 2017, liabilities of $127 and $241, respectively were included in Accrued liabilities on our Condensed Consolidated Balance Sheets.