Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Summary of Stock Option Activity

A summary of the stock option activity is as follows:

						Weighted
				Weighted		Average
				Average		Remaining	Aggregate
				Exercise		Contractual	Intrinsic
(in thousands, except per share amounts and term information)	Shares			Price		Term	Value
Outstanding at December 31, 2021		13,568		$	7.55	7.3 years	$	341,929
Granted		7,580			8.09
Exercised		(2,192	)		4.16
Expired / Cancelled / Forfeited		(1,691	)		12.64
Outstanding at December 31, 2022		17,265		$	7.72	7.3 years	$	5,321
Exercisable at December 31, 2022		7,949		$	6.60	5.4 years	$	5,321

Assumptions Used in Black-Scholes Model to Determine Fair Value for Stock Option Awards Granted

The fair value of option awards issued with service or performance vesting conditions are estimated on the grant date using the Black-Scholes option pricing model. The following table summarizes the assumptions used:

	Year Ended December 31,
	2022		2021		2020
Risk-free interest rate	1.7% - 3.8%		0.9% - 1.3%		0.4% - 1.4%
Expected term	5.7 - 6.1 years		5.7 - 6.1 years		5.3 - 6.3 years
Expected stock price volatility	60% - 77.5%		57.5% - 60%		50% - 62%
Dividend yield		—		—		—
Fair value of common stock per share	$5.25 - $22.02		$16.79 - $24.48		$5.94 - $33.00

Summary of Restricted Stock Activity

A summary of the Restricted Stock Awards and Restricted Stock Unit activity is as follows:

	Restricted			Restricted Stock Units for Class A			Restricted Stock Units for Class B			Weighted Average
	Stock			Common			Common			Grant Date
(in thousands, except per share amounts)	Awards			Stock			Stock			Fair Value
Nonvested restricted stock awards or restricted    stock units at December 31, 2021		939			4,431			5,645		$	29.64
Granted		—			19,643			—			7.76
Vested		(470	)		(2,664	)		(2,053	)		23.42
Forfeited		—			(2,949	)		—			16.67
Nonvested restricted stock awards or restricted    stock units at December 31, 2022		469			18,461			3,592		$	13.69