SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Inputs used in valuation of awards

The following principal inputs were used in the valuation of awards issued for the years ended December 31, 2021 and 2020:

	Year Ended December 31,
	2021	2020
Expected volatility	82.0% - 86.5%	84.1% - 87.4%
Expected term (years)	5.0 – 7.0	0.3 – 7.0
Risk-free interest rate	1.3% - 1.7%	0.5% - 1.4%
Expected dividend yield	0%	0%
Value of underlying share	$1.02 - $4.70	$2.40 - $7.13

Detail of the number of stock options outstanding

Detail of the number of stock options outstanding for the years ended December 31, 2021 and 2020 under the 2015 and 2018 plans is as follows:

	Number of Options	Weighted- Average Exercise Price per Option		Weighted- Average Remaining Contract Term (in years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2020	3,330,206	$	3.93	7.83	$	4,955,658
Granted	1,290,662	3.56
Exercised	(8,261)	3.64
Forfeited (and expired)	(1,268,724)	5.57
Outstanding as of December 31, 2021	3,343,883	$	3.16	7.54	$	1,039,229
Exercisable/vested as of December 31, 2021	2,003,375	$	2.56	5.54	$	941,729

Details of the number of restricted share awards outstanding

Details of the number of restricted share units outstanding under the 2018 Plan is as follows:

	Number of Shares	Weighted- Average Grant Date Fair Value
Outstanding as of December 31, 2020	456,675	$	6.47
Granted	2,160,313	2.50
Forfeited	(584,290)	5.07
Vested	(182,727)	5.40
Outstanding as of December 31, 2021	1,816,851	$	2.28