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.

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 stock options. Stock options generally vest over four years and expire seven years from the 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.


	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, 2021	242	$	8.04	4.44	$	—
Granted	—	—
Exercised	—	—
Canceled or expired	(30)	7.27
Outstanding as of March 31, 2022	212	$	8.14	3.25	$	—
Vested and expected to vest at March 31, 2022	212	$	8.14	3.25	$	—
Exercisable at March 31, 2022	148	$	8.35	2.58	$	—

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.


	Number of Restricted Stock Units (in thousands)	Weighted Average Grant Date Fair Value Per Share		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2021	224	$	6.66	0.56	$	1,280
Granted	600	4.78
Released	(111)	6.80
Forfeited	(48)	6.04
Outstanding at March 31, 2022	665	$	4.97	1.32	$	3,700


	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, 2021	—	$	—	0.00
Granted	114	4.78
Released	—	—
Forfeited	—	—
Outstanding at March 31, 2022	114	$	4.78	0.12

In the first quarter of 2022, we granted 600,000 shares of PSUs to members of our management team. Each PSU represents the right to one share of our common stock with vesting subject to: (a) the achievement of specified levels of the volume weighted average closing prices of our common stock during any one hundred (100) day-period between January 1, 2022 and January 1, 2027, subject to certification by the Compensation Committee (“Performance Milestones”); and (b) continued employment with us through the later of each achievement date or service vesting date, which occurs over a three (3) year period commencing on January 1, 2022.


	Number of Market Condition-Based Restricted Stock Units (in thousands)	Weighted Average Grant Date Fair Value Per Share		Weighted Average Remaining Recognition Period (Years)
Outstanding at December 31, 2021	67	$	6.20	1.49
Granted	600	3.63
Released	(6)	$	6.20
Forfeited	(20)	$	6.20
Outstanding at March 31, 2022	641	$	3.80	1.49

The assumptions used to value market condition based restricted stock units granted during the first quarter of 2022 under our equity incentive program are as follows:


Market condition based restricted stock units:
			Three Months Ended March 31, 2022
Expected life (in years)			1.2
Volatility			52%
Interest rate			1.0%
Dividend yield			—

Under the 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 has been reserved for issuance under the ESPP. During the three months ended March 31, 2022, 7,725 shares were purchased under the ESPP. As of March 31, 2022, 198,123 shares were available for future purchase under the ESPP.

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 years ended March 31, 2022 and 2021 is as follows (in thousands):


	Three Months Ended March 31,
	2022		2021
Stock options	$	(43)	$	15
RSUs, RSAs and PSUs	1,187		497
ESPP	(3)		19
Total	$	1,141	$	531

Sales and marketing	$	90	$	224
Research and development	107		318
General and administrative	944		(11)
Total	$	1,141	$	531

As of March 31, 2022, there was $5.2 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 1.7 years. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures.