Our equity incentive program is a long-term retention program that is intended to attract, retain, and provide incentives for employees, consultants, officers, and directors and to align stockholder and employee interests. We may grant time-based options, market condition-based options, stock appreciation rights, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), performance shares, market condition-based performance restricted stock units (“PSUs”), and other stock-based equity awards to employees, officers, directors, and consultants.

On January 18, 2022, our stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”), which provides for a total number of shares reserved and available for grant and issuance equal to 3,525,119 shares plus up to an additional 855,351 shares that are subject to stock options or other awards granted under the 2011 Equity Incentive Plan. On March 30, 2023, our stockholders approved an amendment to the 2021 Plan to increase the number of shares reserved for issuance under the 2021 Plan by 4,621,488 shares.

Under our equity incentive plans, stock options may be granted at prices not less than the fair market value on the date of grant for such stock options. Stock options generally vest over four years and expire seven years from the applicable grant date. Market condition-based stock awards are subject to a market condition whereby the closing price of our common stock must exceed a certain level for a number of trading days within a specified time frame or the awards will be canceled before expiration. RSAs generally vests over one year. RSUs generally vest over three years. Awards granted other than a stock option or a stock appreciation right shall reduce the common stock shares available for grant by 1.75 shares for every share issued.

A summary of our equity incentive program as of September 30, 2023 is as follows (in thousands):

Common stock shares available for grant	5,028
Stock options outstanding	102
RSUs outstanding	728
RSAs outstanding	75
PSUs outstanding	400

The following summarizes time-based stock options activities for the nine months ended September 30, 2023:

	Number of Shares Underlying Stock Options (in thousands)			Weighted Average Exercise Price Per Share	Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2022	140		$	7.57	4.03	$	—
Granted	—			—
Exercised	(21	)		7.57
Canceled or expired	(17	)		7.57
Outstanding as of September 30, 2023	102		$	7.57	0.12	$	—
Vested and expected to vest at September 30, 2023	102		$	7.57	0.12	$	—
Exercisable at September 30, 2023	102		$	7.57	0.12	$	—

The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the exercise price of our common stock for the options that were in-the-money.

The following summarizes RSU activities for the nine months ended September 30, 2023:

	Number of Restricted Stock Units (in thousands)			Weighted Average Grant Date Fair Value Per Share	Weighted Average Remaining Recognition Period (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2022	887		$	5.85	1.31	$	6,226
Granted	77			7.60
Released	(184	)		5.19
Forfeited	(52	)		6.91
Outstanding at September 30, 2023	728		$	6.12	0.98	$	4,812

The aggregate intrinsic value is calculated as the market value as of the end of the reporting period.

The following summarizes RSA activities for the nine months ended September 30, 2023:

	Number of Restricted Stock Awards (in thousands)			Weighted Average Grant Date Fair Value Per Share	Weighted Average Remaining Recognition Period (Years)
Outstanding at December 31, 2022	119		$	5.47	0.39
Granted	75			8.31
Released	(119	)		5.47
Forfeited	—			—
Outstanding at September 30, 2023	75		$	8.31	0.50

The following summarizes PSU activities for the nine months ended September 30, 2023:

	Number of Market Condition-Based Performance Stock Units (in thousands)			Weighted Average Grant Date Fair Value Per Share	Weighted Average Remaining Recognition Period (Years)
Outstanding at December 31, 2022	615		$	3.69	1.12
Granted	—			—
Released	(206	)		3.70
Forfeited	(9	)		6.20
Outstanding at September 30, 2023	400		$	3.63	0.75

Under our 1999 Employee Stock Purchase Plan (“ESPP”), eligible employees may purchase common stock through payroll deductions at a purchase price of 85% of the lower of the fair market value of our common stock at the beginning of the offering period or the purchase date. Participants may not purchase more than 2,000 shares in a six-month offering period or purchase stock having a value greater than $25,000 in any calendar year as measured at the beginning of the offering period. A total of 1.0 million shares of common stock have been reserved for issuance under the ESPP. During the nine months ended September 30, 2023, no shares were purchased under the ESPP. Effective February 1, 2023, our ESPP was discontinued and 193,134 shares expired following the ESPP termination.

Stock-based compensation is based on the estimated fair value of awards, net of estimated forfeitures, and recognized over the requisite service period. Estimated forfeitures are based on historical experience at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The stock-based compensation related to all of our stock-based awards and ESPP for the three and nine months ended September 30, 2023, and 2022 is as follows (in thousands):

		Three Months Ended September 30,					Nine Months Ended September 30,
		2023		2022			2023			2022
Stock options	$	10	$	53		$	(31	)	$	67
RSUs, RSAs and PSUs		810		678			2,557			2,593
ESPP		—		(1	)		—			1
Total	$	820	$	730		$	2,526		$	2,661

Sales and marketing	$	113	$	19		$	110		$	20
Research and development		1		18			(72	)		96
General and administrative		706		693			2,488			2,545
Total	$	820	$	730		$	2,526		$	2,661

As of September 30, 2023, there was $3.3 million of unrecognized compensation cost adjusted for estimated forfeitures related to non-vested stock options, RSUs, RSAs and PSUs granted to our employees and directors. This unrecognized compensation cost will be recognized over an estimated weighted-average period of approximately 1.6 years. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures.