Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2019



Eight Separate Revenue Goals ⁽¹⁾ (in thousands)		Eight Separate Adjusted EBITDA (CEO Performance Award) Goals (in thousands)
Goal #1, $710,058		Goal #9, $125,000
Goal #2, $860,058		Goal #10, $155,000
Goal #3, $1,010,058		Goal #11, $175,000
Goal #4, $1,210,058		Goal #12, $190,000
Goal #5, $1,410,058		Goal #13, $200,000
Goal #6, $1,610,058		Goal #14, $210,000
Goal #7, $1,810,058		Goal #15, $220,000
Goal #8, $2,010,058		Goal #16, $230,000

⁽¹⁾In connection with the business acquisition that was completed during the three months ended June 30, 2018, the revenue goals have been adjusted for the acquiree's Target Revenue, as defined in the CEO Performance Award agreement.

Summary of Restricted Stock Unit Activity

The following table summarizes RSU activity for the three months ended March 31, 2019 (number of units and aggregate intrinsic value in thousands):



	Number of Units		Weighted Average Grant-Date Fair Value		Aggregate Intrinsic Value
Units outstanding, beginning of year	1,655		$	28.34
Granted	5,667		34.32
Released	(290	)	20.91
Forfeited	(46	)	34.43
Units outstanding, end of period	6,986		33.47		$	380,123

Summary of the Stock Option Activity

The following table summarizes stock option activity for the three months ended March 31, 2019 (number of units and aggregate intrinsic value in thousands):



	Number of Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value
Options outstanding, beginning of year	6,458		$	28.24
Granted	—		—
Exercised	(24	)	4.20
Expired / terminated	—		—
Options outstanding, end of period	6,434		28.33		8.83	$	167,827
Options exercisable, end of period	68		4.54		1.69	3,397

Stock-Based Compensation

The following table summarizes the composition of stock-based compensation for the three months ended March 31, 2019 and 2018 (in thousands):



	Three Months Ended March 31,
	2019		2018
Cost of products sold and services delivered	$	226	$	141
Sales, general and administrative expenses	4,681		2,304
Research and development expenses	2,998		1,648
Total stock-based compensation	$	7,905	$	4,093