Stockholders' Equity (Tables)

12 Months Ended

May 31, 2018

The following table summarizes information about stock option activity for the fiscal year ended May 31, 2018:



	Shares		Weighted- average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value (in thousands)
Outstanding at beginning of year - June 1, 2017	1,667,443		$	15.01
Granted	518,498		$	16.78
Exercised	(271,344	)	$	14.83
Forfeited	(204,184	)	$	16.24
Expired	(14,000	)	$	15.75
Outstanding at end of year - May 31, 2018	1,696,413		$	15.42	5.58	$	9,520
Options exercisable at year-end	652,543		$	14.41	3.48	$	4,321
Options expected to vest in future periods	1,043,870		$	16.05	6.90	$	5,199

The following table summarizes information about performance unit award activity for the year ended May 31, 2018:



	Performance Unit Awards		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	361,164		$	18.54
Granted	135,135		$	23.83
Vested	—		$	—
Canceled	(44,443	)	$	22.76
Non-vested at end of year, May 31, 2018	451,856		$	19.75

The following table summarizes information about restricted stock unit activity for the year ended May 31, 2018:



	Restricted Stock Units		Weighted Average Grant-Date Fair Value
Non-vested at beginning of year, June 1, 2017	439,297		$	15.55
Granted	299,392		$	16.60
Vested	(158,756	)	$	16.83
Canceled	(105,431	)	$	18.25
Non-vested at end of year, May 31, 2018	474,502		$	16.23

The following tables represents the break out of share-based compensation included in the Company's consolidated statement of operations:



	Year ended May 31,
(in thousands)	2018		2017			2016
Cost of sales	$	119	$	299		$	172
Research and development	554		314			349
Sales and marketing	1,778		1,762			1,489
General and administrative	5,461		4,026			2,291
Acquisition, restructuring and other items, net	—		(218		)	(1,061		)
	$	7,912	$	6,183		$	3,240