12. SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Valuation Assumptions for Stock Options

The following table summarizes the weighted-average valuation assumptions and weighted-average grant date fair value of options granted during the periods shown below:

		Year Ended December 31,
		2021		2020		2019
Assumptions (weighted-average)
Volatility		120%		111%		78%
Expected term (in years)		4.0		4.0		4.0
Risk-free rate		0.9%		0.3%		1.9%
Expected dividends		0.0%		0.0%		0.0%
Pre-vest forfeiture rate		8.5%		8.5%		8.5%
Grant date fair value of options granted	$	11.72	$	1.20	$	0.37

Schedule of Valuation Assumptions for Stock Options

The following table summarizes activity and positions with respect to options for the periods shown below (in thousands):

			Weighted-	Weighted-average
			average	remaining		Aggregate
			exercise	contractual		intrinsic
Options	Shares		price	term (in years)		value
Outstanding as of December 31, 2018	4,646	$	2.27	7.0	$	-
Granted	1,636		0.65	-		-
Exercised	-		-	-		-
Forfeited or expired	(1,178)		2.66	-		-
Outstanding as of December 31, 2019	5,104		1.66	7.4		122
Granted	68		1.60	-		-
Exercised	(693)		1.44	-		-
Forfeited or expired	(1,198)		2.20	-		-
Outstanding as of December 31, 2020	3,281		1.51	6.6		12,784
Granted	8		14.04	-		-
Exercised	(1,519)		1.75	-		-
Forfeited or expired	(237)		1.23	-		-
Outstanding as of December 31, 2021	1,533	$	1.37	5.6	$	5,645
Vested and expected to vest as of December 31, 2021	1,518	$	1.55	5.6	$	5,584
Exercisable as of December 31, 2021	1,226	$	1.55	5.1	$	4,306

Restricted Stock Unit Activity

The following table summarizes activity and positions with respect to RSUs and PSUs for the three years ended December 31, 2021:

			Weighted-average
	Shares		price
Unvested as of December 31, 2018	1,149	$	0.64
Granted	1,044		0.60
Vested	(978)		0.89
Forfeited	-		-
Unvested as of December 31, 2019	1,215		0.40
Granted	1,462		1.08
Vested	(219)		0.88
Forfeited	(475)		0.77
Unvested as of December 31, 2020	1,983		0.76
Granted	4,179		12.92
Vested	(2,380)		3.11
Forfeited	(1,157)		11.97
Unvested as of December 31, 2021	2,625	$	13.05