XML 59 R39.htm IDEA: XBRL DOCUMENT

STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2022

The following table summarizes the Company’s stock option activity for the period indicated:


	For the Year Ended December 31, 2022
				Weighted Average
	Shares			Exercise Price
Grants outstanding at beginning of the period		8,196,921		$	69.39
Granted		1,777,370			84.70
Exercised		(318,258	)		70.25
Cancelled and forfeited		(525,893	)		109.31
Grants outstanding at end of the period		9,130,140		$	70.04

Grants exercisable at end of the period		4,692,578		$	70.27
Grants vested and expected to vest at end of the period		8,696,519		$	69.05

The weighted-average grant date fair value per share of stock options granted during the years ended December 31, 2022, 2021 and 2020 was $48.82, $48.16 and $61.38, respectively.


			Weighted Average
	Aggregate		Remaining
	Intrinsic Value		Contractual
	(in thousands)		Life (Years)
Options outstanding at December 31, 2022	$	557,927		6.1
Options exercisable at December 31, 2022	$	289,473		5.2
Options vested and expected to vest at December 31, 2022	$	540,503		6.0

Summary of Company's Stock Options Vested and Exercised

The following table summarizes the Company’s shares vested and stock options exercised for each of the periods indicated:


	For the Year Ended December 31,
	2022		2021		2020
	(in thousands)
Aggregate grant date fair value of shares vested	$	140,889	$	79,068	$	80,355
Aggregate intrinsic value of stock options exercised	$	12,150	$	10,622	$	144,750

Summary of Employee Stock Purchase Plan Activity and Expense

The following table summarizes the Company’s ESPP activity for each of the periods indicated:


	For the Year Ended December 31,
	2022		2021		2020
Number of shares purchased		115,124		111,171		102,031
Proceeds received (in millions)	$	7.5	$	7.8	$	7.5

Summary of Stock-Based Compensation Expense by Function Included within Consolidated Statements of Operations and Comprehensive Loss

The following table summarizes stock-based compensation expense by function included within the consolidated statements of operations and comprehensive loss:


	For the Year Ended December 31,
	2022		2021		2020
	(in thousands)
Research and development	$	61,293	$	50,526	$	41,671
Selling, general and administrative		171,725		63,417		66,399
Total stock-based compensation	$	233,018	$	113,943	$	108,070

Summary of Stock-Based Compensation Expense by Grant Type Included within Consolidated Statements of Operations and Comprehensive Loss

The following table summarizes stock-based compensation expense by grant type included within the consolidated statements of operations and comprehensive loss:


	For the Year Ended December 31,
	2022		2021		2020
	(in thousands)
Stock options	$	174,868	$	68,995	$	68,832
Restricted stock awards/units		52,601		40,055		33,457
Employee stock purchase plan		5,549		4,893		5,781
Total stock-based compensation	$	233,018	$	113,943	$	108,070

Restricted Stock Units (RSUs) [Member]

Summary of Restricted Stock Award and Restricted Stock Units Activity

The following table summarizes the Company’s RSU activity for the period indicated:


	For the Year Ended December 31, 2022
				Weighted Average
				Grant Date
	Shares			Fair Value
Grants outstanding at beginning of the period		1,320,206		$	98.69
Granted *		1,044,826			85.39
Vested		(389,761	)		103.05
Forfeited		(145,639	)		93.36
Grants outstanding at end of the period		1,829,632		$	90.59

*Included in this amount are 38,500 RSUs with performance conditions relating to regulatory approval of certain of the Company's product candidates. As of December 31, 2022, none of the performance conditions were probable of being achieved. Accordingly, no stock-based compensation relating to these grants has been recognized. If the performance milestones are achieved within the required time frame, the Company may recognize up to $3.1 million of stock-based compensation related to these grants, which represents the aggregate grant date fair value of these awards. All other stock options and the remaining RSUs granted during the periods presented in the tables above have only service-based vesting conditions and the majority vest over four years.

Stock Options [Member]

Assumptions for Measuring Fair Values of Stocks

The fair values of stock options granted during the periods presented are measured on the date of grant using the Black-Scholes-Merton option-pricing model, with the following assumptions:


	For the Year Ended December 31,
	2022	2021	2020
Risk-free interest rate (1)	1.6 - 4.2%	0.4 - 1.3%	0.1 - 1.3%
Expected dividend yield (2)	—	—	—
Expected term (3)	5.09 years	4.99 years	5.00 years
Expected volatility (4)	52.4 - 72.9%	60.1 - 70.8%	57.3 - 68.2%

(1)

The risk-free interest rate is estimated using an average of Treasury bill interest rates over a historical period commensurate with the expected term of the option that correlates to the prevailing interest rates at the time of grant.

(2)

The expected dividend yield is zero as the Company has not paid any dividends to date and does not expect to pay dividends in the future.

(3)

The expected term is estimated using historical exercise behavior.

(4)

The expected volatility is the implied volatility in exchange-traded options of the Company’s common stock.