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

12 Months Ended

Dec. 31, 2020

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, 2020, 2019 and 2018, consisted of the following (in thousands):

	2020		2019		2018
Cost of sales
Nonqualified stock options	$	1,357	$	1,289	$	870
Research and development
Nonqualified stock options		1,157		961		553
Selling, general and administrative
Nonqualified stock options		7,332		7,132		4,694
Performance-based restricted stock units		2,829		—		—
Restricted stock units		758		—		—
Cash-settled share-based awards		906		—		—
Total selling, general and administrative		11,825		7,132		4,694
Stock-based compensation expense before taxes	$	14,339	$	9,382	$	6,117

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 years ended December 31, 2020, 2019 and 2018:

	2020	2019	2018
Risk-free interest rate	0.29% - 1.67%	1.38% - 2.56%	2.63% - 2.77%
Expected option term	4.0 - 5.0 years	3.0 - 5.0 years	5.0 years
Expected dividend yield	—	—	—
Expected price volatility	38.65% - 45.12%	28.66% - 39.38%	34.06% - 34.32%

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, 2020, 2019 and 2018 (in thousands):

	2020		2019		2018
Total intrinsic value of stock options exercised	$	11,733	$	9,910	$	25,692
Cash received from stock option exercises		5,481		4,837		8,510
Excess tax benefit from the exercise of stock options		1,815		1,654		4,278

Schedule of Share-based Compensation, Stock Options, Activity

Changes in stock options for the year ended December 31, 2020, 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	4,319	$	34.10
Granted	329		39.21
Exercised	(442)		16.17
Forfeited/expired	(264)		42.37
Outstanding at December 31	3,942		35.98	3.97	$	77,350
Exercisable	1,936		29.38	2.95		50,678
Ending vested and expected to vest	3,860		35.79	3.94		76,482

Schedule of Share-based Compensation, PSUs, Activity

Changes in PSUs and RSUs for the year ended December 31, 2020, consisted of the following:

	PSUs				RSUs
			Weighted Average			Weighted Average
	Stock Units		Grant Date		Stock Units	Grant Date
	(In Thousands)		Fair Value		(In Thousands)	Fair Value
Beginning nonvested balance	—		$	—	—	$	—
Granted	122			43.60	34		42.98
Vested	—			—	—		—
Impact of amendments	(20)			43.43	—		—
Nonvested balance at December 31	102			43.63	34		42.98
Expected to vest at December 31, 2020	102	(1)		43.63	34		42.98

(1) Based on the maximum target payout of 100% for one-year awards, as amended, and 200% for two and three-year awards. Each unit will convert to between .75 and 1.25 shares of common stock based upon the rTSR performance of our common stock.

Schedule of Share-based Compensation, PSUs and RSUs, Activity

The fair value of each PSU was estimated as of the grant date using the following assumptions for awards granted in the year ended December 31, 2020:

	2020
Risk-free interest rate	1.1% - 1.3%
Performance period	0.8 - 2.8 years
Expected dividend yield	—
Expected price volatility	40.2% - 56.1%