Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of the activity related to the shares of common stock covered by outstanding options under the plans

A summary of the activity related to the shares of common stock covered by outstanding options is as follows:

	Number of Shares	Weighted Average Exercise Price		Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Balance at December 31, 2020	339,108	$	32.39
Granted	386,017	10.08
Exercised	—	—
Forfeited	(1,509)	12.92
Expired	(851)	1,131.62
Balance at December 31, 2021	722,765	19.22		8.79	$	—
Vested and expected to vest at December 31, 2021	722,765	19.22		8.79	$	—
Exercisable at December 31, 2021	213,156	43.15		8.07	$	—

Schedule of assumptions used in determining fair value of stock options granted using the Black-Scholes option pricing model

For the years ended December 31, 2021, and 2020, the Company determined the fair value of stock options using the Black-Scholes option pricing model with the following assumptions for option grants, respectively:

	Year Ended December 31,
	2021	2020
Expected dividend yield	—	—
Risk-free rate	0.7% - 1.7%	0.5% - 1.9%
Expected option term (in years)	6.1 - 10.0	6.1 - 10.0
Volatility	118% - 128%	111% - 129%

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

A summary of RSU activity for the year ended December 31, 2021 is as follows:

	Number of RSUs	Weighted Average Remaining Contractual Life (years)
Outstanding at December 31, 2020	8,500
Awarded	18,862
Released	(17,932)
Forfeited	—
Outstanding at December 31, 2021	9,430	0.16
Weighted average remaining recognition period (years)	0.16