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.

We granted equity awards under the 2011 Equity Incentive Plan (the "2011 Plan") from July 2011 through November 2020. The 2011 Plan expired on April 5, 2021, and the remaining 3,708,238 authorized shares were cancelled on the 2011 Plan expiration date. 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 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, 2020	828	$	8.16	4.36	$	2,628
Granted	—	—
Exercised	(326)	8.79
Canceled or expired	(260)	7.49
Outstanding as of December 31, 2021	242	$	8.04	4.44	$	—
Vested and expected to vest at December 31, 2021	222	$	8.08	4.40	$	—
Exercisable at December 31, 2021	132	$	8.41	4.11	$	—

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.

We did not grant stock options during 2021. For the year ended December 31, 2020, the weighted average grant date fair value was $2.21. For the years ended December 31, 2020, the aggregate intrinsic value of stock options exercised was $0.1 million.


	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, 2020	802	$	6.98	1.00	$	9,057
Granted	—	—
Released	(325)	7.48
Forfeited	(253)	6.66
Outstanding at December 31, 2021	224	$	6.66	0.56	$	1,280


	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, 2020	130	$	6.53	0.45
Granted	—	—
Released	(130)	6.53
Forfeited	—	—
Outstanding at December 31, 2021	—	$	—	0.00

In the fourth quarter of 2020, we granted 250,000 shares of PSUs to our executives. 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 November 10, 2020 and November 10, 2025, 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 four (4) year-period commencing on

November 10, 2020. The Performance Milestones of the PSUs were fully achieved and certified by the Compensation Committee. In the fourth quarter of 2021, 22,500 shares of the outstanding PSUs, were vested and released.

The following summarizes PSU activities for the year ended December 31, 2021 (in thousands except for weighted average grant date fair value and weighted average remaining recognition period):


	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, 2020	250	$	6.20	2.08

Released	(23)	$	6.20
Forfeited	(160)	$	6.20
Outstanding at December 31, 2021	67	$	6.20	1.49

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 year ended December 31, 2021, 25,033 shares were purchased under the ESPP with average purchase price of $6.00. During the year ended December 31, 2020, 22,556 shares were purchased under the ESPP with average purchase price of $5.96. As of December 31, 2021, 205,848 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 December 31, 2021 and 2020 is as follows (in thousands):


	For the Years Ended December 31,
	2021		2020
Stock options	$	386	$	1,062
RSUs, RSAs and PSUs	1,894		3,638
ESPP	58		56
Total	$	2,338	$	4,756

Sales and marketing	$	745	$	846
Research and development	742		870
General and administrative	851		3,040
Total	$	2,338	$	4,756

We use the Black-Scholes-Merton option pricing model to determine the fair value of our time-based options and ESPP shares. All share-based payment awards are amortized on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods.

The determination of the fair value of share-based awards on the date of grant using an option pricing model is affected by our stock price as well as assumptions regarding a number of complex and subjective variables. These variables include actual and projected employee stock option exercise behaviors that impact the expected term, our expected stock price volatility over the term of the awards, risk-free interest rate, and expected dividend.

We use the Monte Carlo Simulation model to value the stock options and restricted stock units with a market condition. Valuation techniques such as a Monte Carlo Simulation model have been developed to value path-dependent awards. The Monte Carlo Simulation model is a generally accepted statistical technique used, in this instance, to simulate a range of our future stock prices.

Expected term — We estimate the expected term of options granted by calculating the average term from our historical stock option exercise experience. The expected term of ESPP shares is the length of the offering period.

Expected volatility — We estimate the volatility of our common stock taking into consideration our historical stock price movement and our expected future stock price trends based on known or anticipated events.

Risk-free interest rate — We base the risk-free interest rate that is used in the option pricing model on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term on the options.

Forfeitures — We are required to estimate future forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. We use historical data to estimate pre-vesting option and RSU forfeitures and record stock-based compensation expense only for those awards that are expected to vest.

As of December 31, 2021, there was $2.5 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 1.4 years. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures.