In June 2018, the 2018 Stock Compensation Plan (the “Compensation Plan”) was established whereby 132,000 shares of the Company’s common stock were reserved for issuance. The Company’s board of directors authorized 76,076 replacement stock options and 53,633 replacement restricted stock units (collectively, the “Replacement Awards”) to eligible employees, directors and consultants for equity awards that had been granted under a previous plan. The Compensation Plan was terminated in September 2018 in connection with the adoption

of the Company’s 2018 Equity Incentive Plan described below and, accordingly, no new awards were available for issuance under the Compensation Plan. The Replacement Awards vested at various times through January 2020.

In September 2018, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2018 Equity Incentive Plan (the “2018 Plan”) which provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock units, performance-based stock awards and other forms of equity compensation to the Company’s employees, directors and consultants. Stock options granted under the 2018 Plan generally vest one-fourth on the first anniversary of the vesting commencement date with the balance vesting monthly over the remaining three years. Restricted stock units granted under the 2018 Plan generally vest one third on the first anniversary of the vesting commencement date and one sixth every six months thereafter such that the award will be fully vested on the third anniversary of the vesting commencement date. As of December 31, 2021, 188,307 shares of common stock were reserved for future issuance pursuant to the 2018 Plan which included (1) those shares reserved but unissued under the Compensation Plan and (2) shares of common stock subject to or issued pursuant to awards granted under the Compensation Plan that expired or otherwise terminated or were forfeited. The number of shares available for issuance under the 2018 Plan also includes an annual increase on the first day of each fiscal year equal to the lesser of (1) 65,285 shares; (2) 5% of the outstanding shares of our common stock as of the last day of the immediately preceding fiscal year; or 3) such other amount as the Company’s board of directors may determine. On January 1, 2021, the annual increase of 65,285 additional shares of common stock were available for future grants under the 2018 Plan.

In March 2020, the Company adopted the 2020 Inducement Equity Incentive Plan (the “2020 Plan”) for the purpose of attracting, retaining and incentivizing employees in furtherance of the Company’s success. The 2020 Plan was adopted without stockholder approval pursuant to Rule 303A.08 of the New York Stock Exchange. The 2020 Plan is used to offer equity awards as material inducements for new employees to join the Company. Upon adoption of the 2020 Plan, 32,000 shares of common stock were reserved for the granting of inducement stock options, restricted stock awards, restricted stock units and other forms of equity awards. As of December 31, 2021, 9,000 shares of common stock were reserved for future issuance under the 2020 Plan.

The following is a summary of stock option activity for employees of continuing operations and discontinued operations for the year ended December 31, 2021:

	Stock Options			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020
2018 Plan		124,171		$	363.31
2020 Plan		18,000		$	25.50
		142,171		$	320.54
Forfeited		(33,723	)	$	240.17
Outstanding at December 31, 2021		108,448		$	345.54		5.82	$	—
Exercisable at December 31, 2021		88,324		$	422.83		5.27	$	—
Vested and expected to vest at December 31, 2021		108,448		$	345.54		5.82	$	—

The Company did not grant any stock options during the year ended December 31, 2021. The weighted average grant date fair value of stock options granted during the year ended December 31, 2020 under the 2018 Plan and 2020 Plan was $30.69 and $25.50, respectively. The fair value of the stock options granted during the year ended December 31, 2020 under the 2018 Plan and 2020 Plan was estimated using the Black Scholes option pricing model and the weighted average assumptions set forth below:

	2018 Plan			2020 Plan
Risk-free interest rate		1.30	%		0.50	%
Volatility		58.96	%		58.33	%
Expected dividend yield		0.00	%		0.00	%
Expected life (in years)		5.8			6.3

The following is a summary of the restricted stock unit activity for the 2018 Plan for employees of continuing operations and discontinued operations for the year ended December 31, 2021:

	Restricted Stock Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		33,548		$	21.93
Granted		61,259		$	2.74
Vested		(6,974	)	$	45.12
Forfeited		(17,808	)	$	13.59
Outstanding at December 31, 2021		70,025		$	4.37

In November 2020, the Company granted 266,161 RSAs under the 2018 Plan that were subject to both time-based vesting and the achievement of specific performance goals. During the year ended December 31, 2021, the Company determined that two of the three performance goals had not been achieved. As such, 74,998 RSAs were cancelled, and the previously recognized stock-based compensation expense of approximately $27,000 was reversed.

A summary of the restricted stock award activity for employees of continuing operations and discontinued operations for the year ended December 31, 2021 is presented below:

	Restricted Stock Awards			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020
2018 Plan		286,161		$	4.77
2020 Plan		4,375		$	25.50
		290,536		$	5.08
Granted		103,939		$	4.82
Vested		(88,781	)	$	5.93
Cancelled		(74,998	)	$	4.81
Forfeited		(51,362	)	$	4.81
Outstanding at December 31, 2021		179,334		$	4.71

In September 2018, the Company’s board of directors adopted the 2018 Employee Stock Purchase Plan (the “ESPP”) which permits eligible employees to purchase the Company’s common stock at a discount through payroll deductions during defined offering periods. Eligible employees may elect to withhold up to 15% of their base earnings to purchase shares of the Company’s common stock at a price equal to 85% of the fair market value on the first day of the offering period or the purchase date, whichever is lower. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1 of each fiscal year by the lesser of (1) 11,870 shares, (2) 1.25% of the total number of shares outstanding on December 31 of the preceding fiscal year, or (3) such other amount as the Company’s board of directors may determine.

For the years ended December 31, 2021 and 2020, cash received from the exercise of purchase rights under the ESPP was approximately $0.1 million and $42,000, respectively. As of December 31, 2021, the Company had issued 32,206 shares of common stock under the ESPP, and 4,764 shares of common stock were reserved for future issuance.

Stock-based compensation expense recorded in operating expenses was as follows (in thousands):

	Year Ended December 31,
	2021		2020
Selling, general and administrative	$	1,750	$	3,235
Research and development		304		447
Stock-based compensation expense	$	2,054	$	3,682

Stock-based compensation of $0.1 million and $0.2 million was capitalized to property and equipment and inventory during the years ended December 31, 2021 and 2020, respectively.

Total unrecognized estimated stock-based compensation expense by award type and the remaining weighted average recognition period over which such expense is expected to be recognized at December 31, 2021 was as follows:

	Unrecognized Expense (in thousands)		Remaining Weighted Average Recognition Period (in years)
Stock options	$	313		1.7
Restricted stock awards	$	622		2.2
Restricted stock units	$	252		2.1