Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Compensation Costs Included in Consolidated Statement of Operations for All Stock-based Compensation Arrangements

The compensation cost that has been included in the Consolidated Statements of Operations for the Company’s stock-based compensation plans was as follows:

	Year Ended December 31,
(in thousands)	2021			2020			2019
Selling, general and administrative expense	$	18,924		$	12,622		$	25,968
Research and development expense		6,112			5,259			3,798
Cost of sales		256			264			531
Stock-based compensation expense before taxes		25,292			18,145			30,297
Related income tax benefits		(4,391	)		(3,088	)		(6,191	)
Stock-based compensation expense, net of taxes	$	20,901		$	15,057		$	24,106

Summary of Restricted Stock Units

Following is a summary of RSU activity for the year ended December 31, 2021:

				Weighted
				Average
	Number of			Grant Date
(in thousands, except per share amounts)	Shares			Fair Value
Outstanding at December 31, 2020		994		$	58.94
Granted		412			61.85
Vested		(266	)		55.00
Forfeited		(148	)		60.88
Outstanding at December 31, 2021		992		$	60.91

Schedule of Performance-Based Restricted Stock Units

Following is a summary of PRSU activity for the year ended December 31, 2021:

				Maximum Number
(in thousands, except per share amounts)	Shares			of Shares Eligible to be Issued			Average Grant Date Fair Value
Outstanding at December 31, 2020		619			850		$	57.38
Awarded at target		294			445			59.77
Vested		(105	)		(105	)		53.93
Forfeited		(139	)		(249	)		57.72
Outstanding at December 31, 2021		669			941		$	58.95

Weighted Average Assumptions Used to Estimate Fair Value of Stock Options Granted and Stock Purchase Rights under ESPP

The weighted average assumptions used to estimate the fair value of stock options granted and stock purchase rights under the ESPP are as follows:

	Year Ended December 31,
	2021			2020			2019
ESPP
Volatility		39	%		56	%		35	%
Expected term (years)		0.5			0.5			0.5
Risk free interest rate		0.1	%		0.5	%		2.3	%
Expected dividend yield		—	%		—	%		—	%

Common Stock Reserved for Future Issuance

Common Stock Reserved for Future Issuance

The following table summarizes common shares reserved for issuance on exercise or conversion at December 31, 2021:

(in thousands)
Issued and outstanding RSUs and PRSUs	1,678
Available for issuance under the ESPP	676
Available for future grant	3,359
2023 Notes	7,082
2023 Warrants	6,949
2025 Notes	6,512
2025 Warrants	6,271
Total shares reserved for future issuance	32,527