STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2022

Fair value of options granted is determined using the Black-Scholes option-pricing model with the following weighted average assumptions:

The stock option activity consists of the following:


	Number of Options	Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (1)
Outstanding as of December 31, 2020	24,824	$	172.60	3.9	$	—
Granted	29,932	19.40		4.6	$	—
Exercised	—	—		—	$	—
Forfeited	(165)	—		—	$	—
Expired	(200)	—		—	$	—
Outstanding as of December 31, 2021	54,391	172.60		3.9	$	—
Granted	241,962	5.79		4.8	$	—
Exercised	—	—		—	$	—
Forfeited	(15,343)	—		—	$	—
Expired	(200)	—		—	$	—
Outstanding as of December 31, 2022	280,810	17.00		3.9	$	—
Exercisable as of December 31, 2022	71,131	55.40		3.9	$	—


(1)			The aggregate intrinsic value on the table was calculated based on the difference between the estimated fair value of our stock and the exercise price of the underlying option. The estimated stock values used in the calculation was $5.96 and $19.60 per share for each of the years ended December 31, 2022 and 2021, respectively.

The restricted stock unit activity consists of the following:


	Number of Units	Weighted Average Grant Date Fair Value Per Unit
Outstanding as of December 31, 2020	1,603	$	82.60
Granted	—	—
Vested	(1,570)	84.40
Forfeited	—	—
Outstanding as of December 31, 2021	33	36.00
Granted	19,049	2.87
Vested	(283)	17.67
Forfeited	—	—
Outstanding as of December 31, 2022	18,799	2.71

The stock-based compensation expense was recorded as following (in thousands):


	Years Ended December 31,
	2022		2021
Research and development	$	3	$	3
General and administrative	708		762
Total stock-based compensation expense	$	711	$	765