Stock based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

The fair value of the stock options granted were estimated on the date of grant using a Black-Scholes option pricing model with the following weighted-average assumptions:


	Years Ended December 31,
	2023			2022			2021
Expected stock price volatility	59.2		%	62.1		%	65.4		%
Risk free interest rate	3.9		%	1.7		%	0.6		%
Expected life of options (years)	5.47			5.34			5.40
Expected annual dividend per share	$	—		$	—		$	—

Schedule of Stock Options Activity

A summary of the Company's stock options for the year ended December 31, 2023 were as follows:


	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Years	Aggregate Intrinsic Value
	(in thousands)				(in millions)
Options outstanding, December 31, 2020	14,032	$	9.54
Granted	3,262	$	16.53
Exercised	(1,483)	$	7.05
Forfeited	(844)	$	12.97
Expired	(236)	$	13.28
Options outstanding, December 31, 2021	14,731	$	11.08
Granted	5,733	$	11.53
Exercised	(660)	$	6.58
Forfeited	(495)	$	12.57
Expired	(245)	$	12.84
Options outstanding, December 31, 2022	19,064	$	11.31
Granted	5,733	$	11.99
Exercised	(1,361)	$	7.54
Forfeited	(356)	$	11.59
Expired	(78)	$	15.09
Options outstanding, December 31, 2023	23,002	$	11.69	6.5	$	70.8
Vested and unvested expected to vest, December 31, 2023	21,215	$	11.64	6.3	$	66.5
Exercisable at December 31, 2023	13,431	$	11.26	5.0	$	49.0

Schedule of Non-Vested RSU Activity under the Plan

A summary of non-vested RSU activity under the Plan for the year ended December 31, 2023 is as follows:


	Number of Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Years	Aggregate Intrinsic Value
	(in thousands)				(in millions)
Non-vested units as of December 31, 2020	7,080	$	11.35
Granted	3,191	$	16.94
Vested	(1,863)	$	15.77
Forfeited	(1,067)	$	12.82
Non-vested units as of December 31, 2021	7,341	$	13.90
Granted	5,048	$	11.93
Vested	(2,251)	$	12.48
Forfeited	(421)	$	12.06
Non-vested units as of December 31, 2022	9,717	$	13.07
Granted	4,762	$	13.02
Vested	(3,610)	$	12.21
Forfeited	(836)	$	11.63
Non-vested units as of December 31, 2023	10,033	$	13.37	2.1	$	142.4

Schedule of Equity Compensation Expenses

The following table summarizes information related to compensation expense recognized in the Company's Consolidated Statements of Operations related to the equity awards:


	Years Ended December 31,
(in thousands)	2023		2022		2021
Research and development expense	$	21,470	$	25,089	$	17,340
Selling, general, and administrative expense	64,607		51,423		40,498
Total equity compensation expense	$	86,077	$	76,512	$	57,838