The Company has four equity compensation plans, adopted in 2017, 2013, 2007 and 2004 (the “Plans”) which, taken together, authorize the grant of up to 800,000 shares of common stock to employees, directors, and consultants. On June 5, 2020, the 2017 Omnibus Incentive Plan (the “2017 Plan”) was amended and restated, which increased the number of shares available for issuance under the plan by up to 25,000 shares. This became effective, and was further amended as of June 18, 2021 to increase the number of shares available for issuance under the plan by up to an additional 250,000 shares. On November 22, 2022, the 2017 Plan was further amended and restated, increasing the number of shares available for issuance under the plan by an additional 625,000 shares. Additionally, on June 14, 2017, the Company adopted its 2017 Employee Stock Purchase Plan (the “ESPP”), which authorizes the issuance of up to 50,000 shares of common stock for future issuances to eligible employees.

During 2022, the Company entered into Salary Deduction and Stock Purchase Agreements (the "Purchase Agreements") with certain of its directors and executive officers. Under the Purchase Agreements, on each payroll date, the Company is authorized by the director or executive officer, in advance, to deduct a certain amount of the individual's after-tax base salary. This deducted amount is used to purchase a number of shares of the Company’s common stock determined using the Nasdaq Official Closing Price per share on the applicable payroll date. During the year ended December 31, 2022, directors and executive officers purchased a total of 73,030 shares of common stock at an average price of $6.60 per share.

The total fair value of stock options vested and recorded as compensation expense during the years ended December 31, 2022 and 2021 was $5.5 million and $8.4 million, respectively. As of December 31, 2022, $5.4 million of unrecognized cost related to non-vested stock options was expected to be recognized over a weighted-average period of approximately 1.50 years. The total intrinsic value of options exercised was approximately $0 and $0.2 million for the years ended December 31, 2022 and 2021, respectively.

The following table summarizes the status of the Company’s stock option activity granted under the Plans and 2017 Plan to employees, directors, and consultants (in thousands, except stock option amounts and exercise price): Stock options granted have a contractual term of 10 years and vest over a 2-4 year period. The following table summarizes the status of the Company’s stock option activity granted under the Plans and 2017 Plan to employees, directors, and consultants (in thousands, except stock option amounts):


	Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2021		632,912		$	179.00		4.88	$	—
Granted		106,395			13.00		—		—
Forfeited and expired		(102,536	)		195.80		—		—
Outstanding at December 31, 2022		636,771		$	148.80		4.67	$	—
Vested and exercisable at December 31, 2022		468,834		$	174.40		4.74	$	—

The Company determines the fair value of stock option awards on the grant date using the Black-Scholes option pricing model, which is impacted by assumptions regarding a number of highly subjective variables. The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes option pricing model during the periods indicated:


	Year Ended December 31,
	2022			2021
Weighted average grant date fair value	$	13.00		$	75.40
Expected dividend yield		—	%		—	%
Expected stock price volatility		68	%		68	%
Risk-free interest rate		3.01	%		1.29	%
Expected life of options (in years)		6.2			6.2

The total fair value of restricted stock awards vested and recorded as compensation expense during the years ended December 31, 2022 and 2021 was $0.8 million and $0.6 million respectively. Restricted stock awards cliff vest on the anniversaries of their grant date. As of December 31, 2022, $1.5 million of unrecognized cost related to non-vested restricted stock awards were expected to be recognized over a weighted-average period of approximately 2.67 years.

The following table summarizes the status of the Company's restricted stock awards.


	Shares of Restricted Stock			Weighted Average Fair Value
Nonvested at December 31, 2021		47,055		$	77.20
Granted		2,500			16.60
Forfeited		(15,224	)		75.80
Vested		(10,619	)		73.60
Nonvested at December 31, 2022		23,712		$	66.40

The Employee Stock Purchase Plan (the "ESPP") is available to eligible employees (as defined in the plan document). Under the ESPP, shares of the Company’s common stock may be purchased at a discount (15%) of the lesser of the closing price of the Company’s common stock on the first trading or the last trading day of the offering period. The current offering period extends from December 1, 2022 to May 31, 2023. The Company expects to offer six-month offering periods after the current period. The 2017 Plan reserved 50,000 shares of common stock for issuance under the ESPP. Stock-based compensation related to the ESPP amounted to $0.1 million and $0.2 million for the years ended December 31, 2022 and 2021, respectively. The Company issued 11,542 and 4,078 shares of common stock to participants during the years ended December 31, 2022 and 2021, respectively.

The components of stock-based compensation and the amounts recorded within research and development expenses and selling, general, and administrative expenses in the Company’s consolidated statements of operations and comprehensive loss consisted of the following for the years ended December 31, 2022 and 2021, (in thousands):


	Year Ended December 31,
	2022		2021
Stock options	$	5,516	$	8,441
Restricted stock expense		750		616
Stock awarded to directors and officers		—		—
Employee stock purchase plan		60		150
Total stock-based compensation expense	$	6,326	$	9,207
Cost of sales	$	111	$	208
Research and development expenses		1,629		2,700
Selling, general, and administrative expenses		4,586		6,299
Total stock-based compensation expense	$	6,326	$	9,207