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

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [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, 2019, 2018 and 2017, consisted of the following (in thousands):

	2019		2018		2017
Cost of sales	$	1,289	$	870	$	632
Research and development		961		553		376
Selling, general and administrative		7,132		4,694		3,067
Stock-based compensation expense before taxes	$	9,382	$	6,117	$	4,075

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:

	2019	2018	2017
Risk-free interest rate	1.38% - 2.56%	2.63% - 2.77%	1.77% - 1.83%
Expected option term	3.0 - 5.0 years	5.0 years	5.0 years
Expected dividend yield	—	—	—
Expected price volatility	28.66% - 39.38%	34.06% - 34.32%	33.81% - 34.07%

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, 2019, 2018 and 2017 (in thousands):

	2019		2018		2017
Total intrinsic value of stock options exercised	$	9,910	$	25,692	$	9,264
Cash received from stock option exercises		4,837		8,510		5,552
Excess tax benefit from the exercise of stock options		1,654		4,278		2,264

Schedule of Share-based Compensation, Stock Options, Activity

Changes in stock options for the year ended December 31, 2019, consisted of the following (shares and intrinsic value in thousands):

	Number	Weighted Average		Remaining Contractual	Intrinsic
	of Shares	Exercise Price		Term (in years)	Value
Beginning balance	3,507	$	26.30
Granted	1,244		52.45
Exercised	(288)		16.48
Forfeited/expired	(144)		37.86
Outstanding at December 31	4,319		34.10	4.40	$	23,512
Exercisable	1,532		21.98	3.07		16,403
Ending vested and expected to vest	4,186		33.77	4.36		23,344

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, 2019 (shares in thousands):

	Options Outstanding				Options Exercisable
		Weighted Average	Weighted
	Number	Remaining Contractual	Average Exercise		Number	Weighted Average
Range of Exercise	Outstanding	Life (in years)	Price		Exercisable	Exercise Price
$9.95 - $17.27	1,052	2.27	$	15.04	795	$	14.62
$18.80 - $25.89	335	3.32	$	20.36	200	$	20.25
$28.20	914	4.26	$	28.20	335	$	28.20
$28.93 - $50.50	957	5.29	$	42.02	202	$	42.36
$51.31 - $57.26	1,061	6.18	$	55.28	—	$	—
$9.95 - $57.26	4,319				1,532