Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

The Company recorded stock-based compensation expense in the consolidated statements of operations as follows (in thousands):

	Year Ended December 31,
	2022		2021		2020
Cost of sales	$	1,032	$	—	$	—
Research and development	66,565		86,928		55,955
Selling, general, and administrative	62,703		96,698		72,080
Total stock-based compensation expense	$	130,300	$	183,626	$	128,035

Schedule of Option and Appreciation Rights Activity

The following is a summary of stock options and SARs activity under the 2015 Plan and the 2005 Plan for the year ended December 31, 2022:

	2015 Plan			2005 Plan
	Stock Options	Weighted- Average Exercise Price		Stock Options	Weighted- Average Exercise Price
Outstanding at January 1, 2022	3,635,837	$	42.60	68,225	$	109.52
Granted	633,626	$	65.32	—	$	—
Exercised	(134,222)	$	15.64	(3,000)	$	31.10
Canceled	(81,951)	$	90.83	(1,500)	$	121.00
Outstanding at December 31, 2022	4,053,290	$	46.07	63,725	$	112.94
Shares exercisable at December 31, 2022	2,892,161	$	39.58	63,725	$	112.94

Schedule of Assumptions Used in Estimation of Fair Value of Stock

The fair value of stock options granted under the 2015 Plan was estimated at the date of grant or the date upon which the 2015 Plan was approved by the Company’s stockholders for certain stock options granted in 2020 and 2019 using the Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2022	2021	2020
Weighted average Black-Scholes fair value of stock options and SARs granted	$55.32	$158.02	$80.48
Risk-free interest rate	1.4%-4.3%	0.5%-1.3%	0.2%-1.5%
Dividend yield	—%	—%	—%
Volatility	120.5%-140.1%	124.7%-142.0%	116.0%-152.2%
Expected term (in years)	4.0-6.3	4.1-6.1	3.9-7.6

The ESPP is considered compensatory for financial reporting purposes. As such, the fair value of ESPP shares was estimated at the date of grant using the Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2022	2021	2020
Range of Black-Scholes fair values of ESPP shares granted	$23.59-$79.74	$83.47-$238.85	$2.57-$92.67
Risk-free interest rate	0.6%-3.3%	0.1%-0.2%	0.2%-2.6%
Dividend yield	—%	—%	—%
Volatility	103.0%-142.9%	114.9%-159.4%	66.6%-189.7%
Expected term (in years)	0.5-2.0	0.5-2.0	0.5-2.0

Schedule of Restricted Stock Units Activity

The following is a summary of RSU activity for the year ended December 31, 2022:

	Number of Shares	Per Share Weighted- Average Fair Value
Outstanding and unvested at January 1, 2022	819,828	$	116.70
Restricted stock units granted	1,882,987	$	48.51
Restricted stock units vested	(505,009)	$	89.77
Restricted stock units forfeited	(163,232)	$	99.58
Outstanding and unvested at December 31, 2022	2,034,574	$	61.65