STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-based Compensation Recorded in Consolidated Statements of Operations and Comprehensive Loss

Total stock-based compensation recorded in the consolidated statements of operations and comprehensive loss during the years ended December 31, 2021 and 2020 consisted of the following:

	Years Ended December 31,
	2021		2020
Cost of revenues	$	10,996	$	1,400
Research and development		9,973		1,183
Selling, general and administrative		11,588		1,635
Total stock-based compensation expense	$	32,557	$	4,218

Summary of Stock Option Activity

The following summarizes the stock option activity of the 2013 Plan for the years ended December 31, 2021 and 2020:

	Options to Purchase Common Stock			Weighted- Average Exercise Price per Share		Weighted- Average Grant Date Fair Value per Share		Weighted- Average Remaining Contract Life (In Years)		Aggregate Intrinsic Value
Outstanding — at January 1, 2020		27,263,775		$	0.97	$	0.50		7.95	$	11,941
Granted		90,597			1.41		0.78
Exercised		(2,771,051	)		0.36				3.21		2,565
Forfeited		(1,508,243	)		1.26
Expired		(986,352	)		1.05
Outstanding — at December 31, 2020		22,088,726		$	1.03	$	0.53		7.12	$	85,853
Granted		—			—		—		—		—
Exercised		(3,708,786	)		1.00		0.51		4.32		41,822
Forfeited		(857,579	)		1.21		0.60		0.01		9,131
Expired		(177,033	)		1.16		0.31		—		1,969
Outstanding — at December 31, 2021		17,345,328		$	1.03	$	0.54		6.03	$	195,111
Options vested and exercisable — at December 31, 2021		15,112,440		$	1.01	$	0.52		5.90	$	170,320
Options vested and exercisable — at December 31, 2020		14,739,214		$	0.97	$	0.49		6.83	$	57,660

Summary of Weighted-average Assumptions

The following weighted-average assumptions were used in the Black-Sholes option-pricing model calculation for stock options granted for the years ended December 31, 2021 and 2020:

	2021			2020
Fair value per share of common stock	$	—		$	1.41
Expected volatility		—	%		60.0	%
Risk-free interest rate		—	%		0.6	%
Expected life (years)		—		6.25
Dividend rate	None			None

Summary of Performance-based Restricted Stock Unit Activity

The following summarizes the performance-based restricted stock unit activity of the Plan for the years ended December 31, 2021 and 2020:

	Number of Units			Weighted- Average Grant Date Fair Value
Outstanding — at January 1, 2020		6,818,453		$	1.41
Granted		5,954,361			1.25
Forfeited		(941,759	)		1.40
Outstanding — at December 31, 2020		11,831,055			1.33
Granted		6,542,426			9.68
Forfeited		(1,426,559	)		2.10
Outstanding — at December 31, 2021		16,946,922		$	4.49
Units expected to vest — at December 31, 2021		16,946,922		$	4.49
Units expected to vest — at December 31, 2020		—		$	—