Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2022

Stock-Based Compensation Expense

The following table presents stock-based compensation expense in the Company’s consolidated statements of comprehensive income:

	For the Years Ended December 31,
	2022		2021		2020
	(Amounts in thousands)
Cost of product revenue	$	2,525	$	2,021	$	1,929
Research and development		2,622		2,856		1,534
Selling, general and administrative		22,169		22,623		13,544
Total stock-based compensation	$	27,316	$	27,500	$	17,007

Estimated Weighted Average Assumptions

The fair value of stock option awards granted during the years ended December 31, 2022, 2021 and 2020 were calculated using the following estimated assumptions:

	For the Years Ended December 31,
	2022	2021	2020
Expected term (in years)	5.5-6.5	5.5-6.5	5.5-6.5
Expected volatility (range)	41.44-43.96%	44.57-45.27%	45.14-50.87%
Risk-free interest rate	1.86-4.07%	0.77-1.07%	0.34-1.15%
Expected dividend yield	0%	0%	0%

Summary of Option Activity

Information regarding option activity for the year ended December 31, 2022, under the Plans is summarized below:

	Shares			Weighted average exercise price		Weighted- Average Remaining Contractual Term (in Years)		Aggregate Intrinsic Value (in Thousands)
Options outstanding at December 31, 2021		625,107		$	54.15
Granted		87,838		$	190.90
Exercised		(86,980	)	$	42.62
Forfeited/expired/cancelled		(16,000	)	$	196.79
Options outstanding at December 31, 2022		609,965		$	71.74
Options exercisable at December 31, 2022		317,218		$	47.93
Vested and expected to vest at December 31, 2022(1)		594,350		$	71.30		5.85	$	61,155

(1)Represents the number of vested options as of December 31, 2022 plus the number of unvested options expected to vest as of December 31, 2022, based on the unvested outstanding options at December 31, 2022 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

Summary of Restricted Stock Unit Activity

Information regarding stock unit activity, which includes activity for restricted stock units and performance stock units, for the year ended December 31, 2022 under the Plans is summarized below:

	Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2021		606,685		$	115.11
Awarded		194,633		$	191.61
Vested		(208,531	)	$	98.90
Forfeited/cancelled		(61,753	)	$	161.05
Unvested at December 31, 2022		531,034		$	142.57
Vested and expected to vest at December 31, 2022(1)		505,611		$	138.17

(1)Represents the number of vested stock units as of December 31, 2022, plus the number of unvested stock units expected to vest as of December 31, 2022, based on the unvested outstanding stock units at December 31, 2022 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.