On October 31, 2017, the Company adopted the 2017 Stock Option and Incentive Plan (“2017 Plan”). Upon the adoption of the 2017 Plan, no further grants would be made under the 2011 Stock Incentive Plan (“2011 Plan”). The 2017 Plan initially provided for the grant of awards for 2,038,021 shares of common stock. In addition to the shares available for grant under the 2017 Plan, shares underlying any awards outstanding under the 2011 Plan as of October 31, 2017 that are cancelled, forfeited or otherwise terminated without being exercised will be available for future grant under the 2017 Plan. The 2017 Plan also provides that an additional number of shares will automatically be added to the shares authorized for issuance under the 2017 Plan on January 1 of each year. The number of shares added each year will be equal to the lesser of: (i) 4% of the outstanding shares on the immediately preceding December 31 or (ii) such amount as determined by the Compensation Committee of the registrant’s Board of Directors. On January 1, 2020, 2021 and 2022, the shares available for grant under the 2017 Plan were automatically increased by 989,400, 2,032,854 and 3,318,776 shares, respectively.

All of the Company’s employees, officers, directors, consultants and advisors are eligible to be granted options, restricted stock units (“RSUs”), and other share-based awards under the terms of the 2017 Plan. As of March 31, 2022, 2,590,678 shares of common stock were available for future grant under the 2017 Plan.

On January 22, 2021, the Company adopted the 2021 Inducement Equity Plan (“2021 Plan”). The 2021 Plan provides for the grant of awards for 1,600,000 shares of common stock. The purpose of the 2021 plan is to enable the Company to grant equity awards to induce highly qualified prospective officers and employees who are not currently employed by the Company to accept employment and provide them with an equity interest in the Company. The Company is utilizing the 2021 Plan for awards the Company may make without stockholder approval as an inducement pursuant to Rule 5635(c)(4) of the Marketplace Rules of the Nasdaq Stock Market, Inc. As of March 31, 2022, 1,111,375 shares of common stock were available for future grant under the 2021 Plan.

All stock option grants are nonstatutory stock options except option grants to employees (including officers and directors) intended to qualify as incentive stock options under the Internal Revenue Code of 1986, as amended. Incentive stock options may not be granted at less than the fair market value of the Company’s common stock on the date of grant, as determined in good faith by the Board of Directors at its sole discretion. Nonqualified stock options may be granted at an exercise price established by the Board of Directors at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Vesting periods are generally four years and are determined by the Board of Directors or a delegated subcommittee. Stock options become exercisable as they vest. Options granted under the 2011 Plan, 2017 Plan and 2021 Plan expire no more than 10 years from the date of grant.

Stock-based compensation expense included in the Company’s statements of operations and comprehensive loss is as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Research and development	$	170	$	247
General and administrative		447		620
Total	$	617	$	867

The Company did not grant any stock options during the three months ended March 31, 2022. A summary of the stock option activity under the 2011, 2017 and 2021 Plans during the three months ended March 31, 2022 is as follows:


	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021		6,765,837		$	2.81		7.6	$	3
Granted		—			—
Exercised		—			—
Forfeited		(1,015,125	)		2.29
Expired		(13,176	)		0.42
Outstanding at March 31, 2022		5,737,536			2.90		7.3	$	—
Exercisable at March 31, 2022		3,211,793		$	3.49		6.3	$	—

As of March 31, 2022, total unrecognized stock-based compensation expense relating to unvested stock options was $3.8 million. This amount is expected to be recognized over a weighted-average period of 2.3 years.

On February 1, 2022, the Company awarded 2,998,500 RSUs to employees of the Company as part of the Retention Plan. The RSUs vest over a three-year period ratably on July 15th and January 15th of each year following grant date. The RSUs are generally forfeited if the employment relationship terminates with the Company prior to vesting.


	Shares			Weighted-Average Grant Date Fair Value
Nonvested at December 31, 2021		—		$	—
Granted		2,998,500			0.40
Vested		—			—
Forfeited		(747,000	)		0.40
Nonvested at March 31, 2022		2,251,500		$	0.40

As of March 31, 2022, the total remaining unrecognized compensation cost related to all nonvested RSUs amounted to $0.9 million. This amount is expected to be recognized over a weighted-average period of 2.8 years.