In connection with the adoption of the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”) in August 2018, the Company ceased granting stock options under the Company’s 2011 Employee Equity Plan (the “2011 Plan”). However, the 2011 Plan will continue to govern the terms and conditions of the outstanding stock options previously granted thereunder. Any shares of stock related to awards outstanding under the 2011 Plan that terminate by expiration, forfeiture, cancellation, or otherwise without the issuances of such shares will become available for grant under the 2018 Plan. Stock options granted under the 2011 Plan expire in five or ten years from the date of grant.

In August 2018, the Company’s board of directors adopted, and its stockholders approved, the 2018 Plan, which allows for the granting of stock, stock options, and stock appreciation rights awards to employees, advisors and consultants. Stock options granted under the 2018 Plan may be either incentive stock options or non-statutory stock options. Incentive stock options may be granted to employees, advisors and consultants at exercise prices of no less than the fair value of the common stock on the grant date. If at the time of grant, the optionee owns stock representing more than 10% of the voting power of all classes of stock of the Company, the exercise price must be at least 110% of the fair value of the common stock on the grant date as determined by the board of directors. Non-statutory stock options may be granted to employees, advisors and consultants at exercise prices of less than the fair market value of a share of common stock on the date the non-statutory stock option is granted but shall under no circumstances be less than adequate consideration as determined by the board of directors for such a share. The vesting period of stock option grants is determined by the board of directors, ranging from zero to eight years. Stock options granted under the 2018 Plan expire in five or ten years from the date of grant.

The Company initially reserved 425,000 shares of common stock for issuance, subject to certain adjustments, pursuant to awards under the 2018 Plan. Any shares of common stock related to awards outstanding under the 2011 Plan as of the effective date of the 2018 Plan, which thereafter terminate by expiration, forfeiture, cancellation or otherwise without the issuance of such shares, will be added to, and included in, the number of shares of common stock available for grant under the 2018 Plan. In addition, effective January 1, 2020 and continuing until the expiration of the 2018 Plan, the number of shares of common stock available for issuance under the 2018 Plan will automatically increase annually by 2% of the total number of issued and outstanding shares of the Company’s common stock as of December 31^st of the immediately preceding year or such lesser number as the Company’s board of directors may decide, which may be zero. Accordingly, on January 1, 2021, 447,744 additional shares of common stock became available for issuance under the 2018 Plan.

A summary of the Company’s stock option activity and related information is as follows:

	Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Balance as of January 1, 2021		832,868		$	6.83		6.9	$	2
Granted		334,088			2.53
Exercised		-			-
Forfeited		(19,499	)		5.83
Balance as of September 30, 2021		1,147,457		$	5.58		7.1	$	5
Exercisable as of September 30, 2021		657,449		$	7.28		5.9	$	3

The weighted-average grant date fair value of stock options granted to employees and directors for the nine months ended September 30, 2021 and 2020 was $2.53 per share and $2.73 per share, respectively. The aggregate grant date fair value of stock options that vested during the nine months ended September 30, 2021 and 2020 was $309,081 and $719,632, respectively.

The intrinsic value of stock options vested and exercisable and expected to vest and become exercisable is calculated based on the difference between the exercise price and the fair value of the Company’s common stock as of September 30, 2021 and December 31, 2020. The intrinsic value of exercised stock options is the difference between the fair value of the underlying common stock and the exercise price as of the exercise date.

As of September 30, 2021 and December 31, 2020, total unrecognized compensation cost related to stock options granted to employees was $778,278 and $926,591, respectively, which is expected to be recognized over a weighted-average period of 2.17 and 2.96 years, respectively.

The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Nine Months Ended September 30,
	2021			2020
Expected term (in years)		6.0			6.3
Expected volatility		75	%		75	%
Risk-free interest rate		0.7	%		0.9	%
Expected dividend yield		-	%		-	%

In March 2020, the Company issued 20,000 shares of common stock as compensation for administrative fees incurred in connection with entering into a purchase agreement with Keystone. Pursuant to the terms of the Purchase Agreement, Keystone has agreed to purchase up to $5,000,000 of shares of the Company’s common stock. At the time of issuance, the fair market value of the shares was $4.00, and, as a result, $80,000 was included in general and administrative expenses for the nine months ended September 30, 2020. In January and February 2021, respectively, the Company issued 6,137 and 3,842 shares of the Company’s common stock, respectively to Angel

Pond LLC as compensation for a consulting agreement. At the time of issuance, the fair market value of the shares was $2.44 and $3.90, respectively, and as a result $30,000 was included in general and administrative expenses in the nine months ended September 30, 2021.

Total stock-based compensation expense recognized in the condensed consolidated statements of operations and comprehensive loss is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	45	$	37	$	118	$	96
General and administrative		111		54		270		565
Total stock-based compensation expense	$	156	$	91	$	388	$	661