Accounting for Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Expense

The following table reflects the impact of total compensation expense related to stock-based equity plans on the reported operating results for the respective periods (in millions):

	Year Ended December 31,
	2023			2022			2021
Effect on income before income taxes	$	(22	)	$	(20	)	$	(25	)
Effect on net income	$	(17	)	$	(15	)	$	(20	)

Schedule of Share-based Payment Awards, Stock Options, Valuation Assumptions

The fair value of stock options was estimated using the Black Scholes option pricing model with the following assumptions and weighted-average fair values during the years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
	2023		2022		2021
Expected volatility	87.3%		84.3% - 87.5%		84.3% - 88.9%
Expected dividends		—		—		—
Expected term	6 years		3 - 6 years		3 - 6 years
Risk-free interest rate	4.2%		1.5% - 1.6%		0.3% - 0.9%

Schedule of Share-based Compensation, Stock Options, Activity

Options outstanding and exercisable under the 2009 Plan as of December 31, 2023, and changes during each of the years in the three-year period prior to December 31, 2023, were as follows (in millions, except share and per share data):

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value as of December 31, 2023
Outstanding at December 31, 2020		1,817,525		$	8.77
Granted		749,250			8.81
Exercised		(65,499	)		5.03
Forfeited and cancelled		(199,523	)		33.14
Outstanding at December 31, 2021		2,301,753			6.77
Granted		760,000			10.18
Exercised		(56,500	)		4.97
Forfeited and cancelled		(173,502	)		13.41
Outstanding at December 31, 2022		2,831,751			7.32
Granted		814,000			6.15
Exercised		(15,001	)		4.95
Forfeited and cancelled		—			—
Outstanding at December 31, 2023		3,630,750		$	7.07	7.3 years	$	—
Exercisable at December 31, 2023		2,071,994		$	6.46	6.4 years	$	—

Schedule of Share-based Compensation, Restricted Stock, Activity

Restricted stock outstanding under the 2009 Plan as of December 31, 2023, and changes during each of the years in the three-year period prior to December 31, 2023, were as follows:

	Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2020		4,555,735		$	4.84
Granted		2,929,250			8.16
Vested		(2,312,328	)		4.68
Forfeited		(177,343	)		6.33
Unvested at December 31, 2021		4,995,314			6.30
Granted		3,253,000			8.95
Vested		(2,561,575	)		5.70
Forfeited		(145,674	)		8.89
Unvested at December 31, 2022		5,541,065			8.53
Granted		2,746,000			6.04
Vested		(2,164,570	)		6.85
Forfeited		(68,672	)		8.16
Unvested at December 31, 2023		6,053,823			8.00

Schedule of Share-based Compensation, Restricted Stock Units, Activity

RSUs outstanding under the 2009 Plan as of December 31, 2023, and changes during each of the years in the three-year period prior to December 31, 2023, were as follows:

	Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2020		613,739		$	4.89
Granted		173,664			8.81
Vested		(300,805	)		5.09
Forfeited		—			—
Unvested at December 31, 2021		486,598			6.17
Granted		176,820			9.66
Vested		(151,058	)		5.63
Forfeited		—			—
Unvested at December 31, 2022		512,360			7.54
Granted		365,037			6.15
Vested		(101,471	)		7.75
Forfeited		—			—
Unvested at December 31, 2023		775,926			6.86