Equity Incentive Plans

12 Months Ended

Dec. 31, 2024

Equity Incentive Plans [Abstract]

Equity Incentive Plans

(10) Equity Incentive Plans

(a) Stock Option Plans – Prior to the IPO

Prior to the IPO in June 2021, the Company maintained two equity incentive plans, the 2004 Stock Incentive Plan, as amended, or 2004 Plan, and the 2015 Stock-Based Incentive Compensation Plan, or 2015 Plan, which provided the Company’s employees, non-employee directors, consultants and independent contractors the opportunity to participate in the equity appreciation of the business through the receipt of stock options to purchase shares of common stock. New grants ceased being made under the 2004 Plan upon the adoption of the 2015 Plan; however, outstanding stock options under the 2004 Plan may continue to be exercised in accordance with their terms. The Company adopted the 2015 Plan in April 2015, which contains substantially similar terms and conditions as the 2004 Plan. The 2015 Plan initially had 1,176,681 shares of common stock reserved for issuance under the 2015 Plan and was administered by the compensation committee of the Board of Directors. Upon the closing of the IPO, no further awards will be made under the 2015 Plan; however, outstanding stock options under the 2015 Plan may continue to be exercised in accordance with their terms.

(b) Stock Option Plans – Post the IPO

In June 2021, in connection with the IPO, the 2021 Equity Incentive Plan (2021 Plan) became effective, which was adopted by the Board of Directors in February 2021 and the stockholders approved the 2021 Plan in March 2021. The 2021 Plan is administered by our compensation committee.

Under the 2021 Plan, the Company may grant awards in respect of shares of common stock to employees, consultants, and non-employee directors pursuant to option awards, stock appreciation right, or SAR, awards, restricted stock awards, restricted stock unit, or RSU, awards, performance stock awards, performance stock unit, or PSU, awards, and other stock-based awards.

The total number of shares of common stock available for awards under the 2021 Plan is 1,111,111, provided that such number shall be automatically increased on each January 1, beginning on January 1, 2022, by 4% of the outstanding number of shares of common stock on the immediately preceding December 31 or such lesser number of shares as determined by the Board of Directors. The aggregate number of shares of our common stock that will be available for issuance under awards granted pursuant to the 2021 Plan shall also be increased by the number of shares underlying the portion of an award granted under the 2015 Plan that is cancelled, terminated or forfeited or lapses after the effective date of the 2021 Plan. No more than 1,111,111 shares of common stock issued under the 2021 Plan may be issued pursuant to the exercise of incentive stock options (ISO), provided that such number shall be automatically increased on each January 1, beginning on January 1, 2022, by the lesser of 4% of the outstanding number of shares of common stock on the immediately preceding December 31 or 555,555 shares of common stock. Shares of common stock issued by us in connection with the assumption or substitution of outstanding grants or under certain stockholder approved plans from an acquired company shall not reduce the number of shares of common stock available for awards under the 2021 Plan. Shares of common stock underlying the portion of an award that is forfeited or otherwise terminated for any reason whatsoever, in any case, without the issuance of shares of common stock, will be added back to the number of shares of common stock available for grant under the 2021 Plan. No non-employee director may be granted awards under the 2021 Plan in any one calendar year covering a number of shares of common stock that have a fair market value on the grant date in excess of $350,000 in the first calendar year of such non-employee director’s initial service as a non-employee director and $200,000 in any other calendar year of such non-employee director’s service as a non-employee director.

Options granted under the 2021 Plan may be either ISOs or nonqualified stock options. The price at which shares of common stock may be purchased upon exercise shall be determined by the compensation committee but shall not be less than the fair market value of one share of common stock on the date of grant, or, in the case of an ISO granted to a ten-percent stockholder, less than 110% of the fair market value of a share of common stock on the date of grant. The compensation committee may grant options that have a term of up to 10 years, or, in the case of an ISO granted to a ten-percent stockholder, five years. The award agreement shall specify the exercise price, term, vesting requirements, including any performance goals, and any other terms and conditions applicable to the granted option. Unless otherwise provided in an award agreement or an effective employment, consulting, severance or similar agreement with us or a subsidiary, upon a participant’s termination of service for any reason, the unvested portion of each award of options granted generally will be forfeited with no compensation due to the participant.

Activity under the stock option plans was as follows:

	Number of options			Weighted average exercise price		Aggregate Intrinsic Value
Outstanding at December 31, 2022		931,550		$	3.97
Granted		1,301,200			0.59
Forfeited		(130,720	)		1.97
Outstanding at December 31, 2023		2,102,030		$	2.00
Granted		1,359,821			1.07
Forfeited		(487,632	)		1.84
Outstanding at December 31, 2024		2,974,219		$	1.60		847,758
Vested and exercisable at December 31, 2024		1,308,379		$	2.35		453,514

The intrinsic value represents the amount by which the market price of the underlying stock at December 31, 2024 exceeds the exercise price of an option.

Stock options granted under the 2021 Plan for the years ended December 31 2024 and 2023 were as follows:

	2024		2023
Employee		1,286,921		1,211,200
Nonemployee		72,900		90,000
Total		1,359,821		1,301,200

The Black-Scholes weighted average assumptions for all stock option awards granted during 2024 and 2023 were as follows:

	2024						2023
	2021 Plan			Inducement Grants			2021 Plan
Fair Value of Awards	$	0.91			0.94			0.48
Grant Price	$	1.07			1.1			0.59
Expected term (in years)		6.20			6.25			5.63
Risk‑free interest rate		4.04	%		4.10	%		4.09	%
Dividend yield		—	%		—	%		—	%
Expected volatility		109.61	%		109.64	%		105.33	%

The intrinsic values represent the dollar value of the exercised stock options whereby the fair market value of the underlying common stock exceeded the exercise price of the stock option as of the exercise date. There were no options exercised during 2023 and 2024 .

The options outstanding and vested and currently exercisable by exercise prices as of December 31, 2024 were as follows:

Options outstanding						Options vested and exercisable
				Weighted				Weighted		Weighted
				average		Number of		average		average
Exercise		Outstanding		remaining		options		Exercise		remaining
price		(in shares)		life years		vested		price		life years
$	0.47 - 0.49		1,063,600		8.50		716,950	$	0.49		8.50
	0.50 - 0.80		565,321		9.05		22,867		0.59		8.47
	0.81 - 1.33		564,450		9.40		20,325		0.88		8.42
	1.34 - 1.74		210,846		2.26		85,335		1.67		2.45
	1.75 - 3.14		164,325		7.70		57,225		2.64		7.53
	3.15 - 3.60		237,614		2.49		237,614		3.24		2.49
	3.61 - 13.00		168,063		5.75		168,063		9.68		5.74
			2,974,219		7.65		1,308,379		2.35		6.62

As of December 31, 2024, the total number of shares of common stock reserved for future awards under the 2021 Plan is 623,661.

(c) Inducement Grants

For the year ended December 31, 2022, the Company awarded, outside the 2021 Plan, two stock option grants for the right to purchase a total of 150,000 shares of common stock (inducement grants). For the year ended December 31, 2024, the Company awarded, outside the 2021 Plan, one stock option inducement grant for the right to purchase a total of 100,000 shares of common stock. The grants were approved by the Compensation Committee, and vest in equal installments over four years provided the employee remains employed by the Company on the vesting date.

The inducement grants are summarized as follows:

			Weighted		Weighted
			average		average
	Number of		exercise		remaining
	options		price		life years
Outstanding at December 31, 2023		150,000	$	2.42		8.40
Granted		100,000		1.10		9.12
Outstanding at December 31, 2024		250,000	$	1.89		8.07
Vested and exercisable at December 31, 2024		75,000	$	2.42		7.36

(d) Valuation

The Company uses the Black‑Scholes option pricing model to determine the fair value of stock awards granted to employees and non-employees. The determination of the fair value of share‑based payment awards granted using a pricing model is affected by the Company’s stock price as well as the assumptions regarding a number of complex and subjective variables as follows:

(i) Expected Term

The expected term of stock options represents the period where the stock options are expected to remain outstanding. The Company’s historical share option exercise experience does not provide a reasonable basis upon which to estimate an expected term because of a lack of sufficient data. Therefore, the Company estimates the expected term for all options granted by using the simplified method provided by the ASC 718, which calculates the expected term as the average of the time-to-vesting and the contractual life of the options. The contractual term for options awarded since inception is 10 years for employees and non-employees.

(ii) Risk‑Free Interest Rate

The risk‑free interest rate is based on U.S. Treasury zero‑coupon issues with remaining terms similar to the expected term on the options.

(iii) Dividend Yield

The Company has not declared or paid any cash dividends from inception through December 31, 2024 and does not plan to pay any cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.

(iv) Expected Volatility

Expected volatility measures the amount that a stock price has fluctuated or is expected to fluctuate during a period. The Company determines volatility based on an analysis of comparable companies.

(v) Forfeitures

The Company accounts for forfeitures as they occur.

(e) Employee Stock Purchase Plan (ESPP)

In June 2021, in connection with the IPO, the ESPP became effective upon adoption by the Board of Directors in February 2021 and the stockholders approved the 2021 ESPP Plan in March 2021. The ESPP is administered by the compensation committee.

The total number of shares of common stock available for purchase under the ESPP is 166,666, provided that such number is automatically increased on January 1 of each calendar year, from January 1, 2022 through January 1, 2031 by the least of (i) 1.0% of the total number of shares of common stock outstanding on December 31 of the immediately preceding calendar year, (ii) 222,222 shares of common stock or (iii) a number determined by the board of directors that is less than the foregoing clauses (i) and (ii).

Under the ESPP, the Company may specify offerings with durations of not more than 27 months and may specify shorter purchase periods within each offering. Each offering will have one or more purchase dates on which shares of common stock will be purchased for employees participating in the offering. An offering may be terminated under certain circumstances. No employee may purchase more than 12,254 shares of common stock under the ESPP during any offering period. Unless otherwise determined by the board of directors, shares of common stock will be purchased for accounts of employees participating in the ESPP at a price per share equal to the lower of (i) 85% of the fair market value of a share of common stock on the last date of an offering period or (ii) 85% of the fair market value of a share of common stock on the first day of such offering period.

As of December 31, 2024, 84,621 shares of common stock have been purchased under the ESPP to date, and the total number of shares of common stock reserved for future awards under the ESPP is 535,356.

(f) Stock‑Based Compensation Expense

Stock‑based compensation expense recognized is based on the value of the portion of stock option awards that is ultimately expected to vest on a straight-line basis. Stock‑based compensation expense recognized in the Company’s statements of comprehensive loss during the years ended December 31, 2024, and 2023 includes compensation expense for stock‑based awards based on the fair value estimated in accordance with the provisions of ASC 718.

The following table shows the stock-based compensation expense related to vested stock option grants to employees and non-employees awarded under the stock plans and inducement grants by financial statement line item on the accompanying statements of comprehensive loss:

	2024		2023
Research and development	$	179,911		159,816
Sales and marketing		48,379		(948	)
General and administrative		215,857		516,832
Total share-based compensation expense	$	444,147		675,700

As of December 31, 2024, the remaining amount of stock‑based compensation expense that is expected to be recognized in future periods for employees and non-employees is $1,311,784 which includes $155,222 of compensation expense to be recognized upon achieving a certain performance condition. The $1,156,562 of unrecognized expense is expected to be recognized over a weighted average period of 2.8 years.