Employee Stock Purchase Plan, Stock Options and Warrants (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The stock-based compensation expense before income tax expense for the years ended December 31, 2017, 2016 and 2015, consisted of the following (in thousands):

	2017		2016		2015
Cost of goods sold	$	632	$	472	$	398
Research and development	376		184		122
Selling, general, and administrative	3,067		1,850		1,723
Stock-based compensation expense before taxes	$	4,075	$	2,506	$	2,243

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

In applying the Black-Scholes methodology to the option grants, the fair value of our stock-based awards granted were estimated using the following assumptions for the periods indicated below:

	2017			2016			2015
Risk-free interest rate	1.77%	-	1.83%	1.15%	-	1.40%	1.53%	-	1.66%
Expected option life	5.0 years			5.0 years			5.0 years
Expected dividend yield	—%			—%			—%
Expected price volatility	33.81%	-	34.07%	34.28%	-	37.06%	33.72%	-	35.11%

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable

The table below presents information related to stock option activity for the years ended December 31, 2017, 2016 and 2015 (in thousands):

	2017		2016		2015
Total intrinsic value of stock options exercised	$	9,264	$	3,648	$	7,548
Cash received from stock option exercises	5,552		4,577		6,227
Excess tax benefit from the exercise of stock options	2,264		669		2,124

Schedule of Share-based Compensation, Stock Options, Activity

Changes in stock options for the year ended December 31, 2017, consisted of the following (shares and intrinsic value in thousands):

	Number of Shares		Weighted Average Exercise Price		Remaining Contractual Term (in years)	Intrinsic Value
Beginning balance	2,817		$	15.32
Granted	1,297		29.31
Exercised	(404	)	14.02
Forfeited/expired	(87	)	18.79
Outstanding at December 31	3,623		20.40		4.57 years	$	82,615
Exercisable	1,110		14.35		2.55 years	32,019
Ending vested and expected to vest	3,484		20.23		4.52 years	80,052

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range

The following table summarizes information about stock options outstanding at December 31, 2017 (shares in thousands):

			Options Outstanding				Options Exercisable
Range of Exercise			Number Outstanding	Weighted Average Remaining Contractual Life (in years)	Weighted Average Exercise Price		Number Exercisable	Weighted Average Exercise Price
$9.95	-	$13.75	925	2.17 years	$	12.65	713	$	12.84
$13.77	-	$17.27	991	4.38 years	$	16.18	294	$	15.96
$18.80	-	$22.00	425	5.00 years	$	20.14	103	$	20.18
$28.20	-	$38.35	1,282	6.30 years	$	29.33	0	$	—
$9.95	-	$38.35	3,623				1,110