The Company has a stock-based compensation plan, the 2011 Incentive Compensation Plan, as amended, (the “2011 Plan”), to attract, motivate, retain and reward employees, directors and consultants by providing its Board or a committee of the Board the discretion to award equity incentives to these persons.

On June 6, 2011, the Company’s stockholders approved the 2011 Plan, which is administered by the Compensation Committee of the Board. The 2011 Plan provides that stock options, stock units, restricted shares, and stock appreciation rights may be granted to executive officers, directors, consultants, and other key employees. The Company reserved 400,000 shares of common stock under the 2011 Plan, plus 459,956 shares of common stock that remained available for delivery under the 2007 Plan and the 2010 Plan as of June 6, 2011. In aggregate, as of June 6, 2011, 859,956 shares were available for future grant under the 2011 Plan, including shares rolled over from 2007 Plan and 2010 Plan. Subsequent to June 6, 2011 through December 31, 2020, the number of shares of common stock authorized for issuance under the 2011 Plan has been increased by 4,400,000 shares.

A summary of activity for the Company’s stock options for the year ended December 31, 2020 follows:

	Number Outstanding			Average Exercise Price per Share		Weighted Average Remaining Contractual Term (Years)		Average Intrinsic Value
Balance at December 31, 2019		562,102		$	5.60	5.86		$	572,869
Granted		—			—				—
Cancelled or Expired		(8,833	)		8.17				—
Exercised		(2,500	)		5.20				—
Balance at December 31, 2020		550,769		$	5.56		4.88	$	1,875,719
Vested or expected to vest at December 31, 2020		550,769		$	5.56		4.88	$	1,875,719
Exercisable at December 31, 2020		550,769		$	5.56		4.88	$	1,875,719

The following table summarizes information about stock options outstanding as of December 31, 2020:

	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$4.36 - $7.20		459,610		5.32	$	4.43		459,610	$	4.43
$7.50 - $11.25		70,698		3.05		9.95		70,698		9.95
$11.30 - $16.95		13,764		1.65		12.90		13,764		12.90
$17.60 - $26.40		6,697		0.74		21.55		6,697		21.55
$4.36 - $26.40		550,769		4.88	$	5.56		550,769	$	5.56

As of December 31, 2020, there was no unrecognized stock-based compensation expense related to stock options.

The following is a summary of RSU activity for the year ended December 31, 2020:

	Number Outstanding			Weighted Average Fair Value
Unvested as of December 31, 2019		1,148,110		$	4.43
Granted		508,928			4.28
Vested		(726,968	)		4.31
Forfeited		(247,507	)		4.71
Unvested as of December 31, 2020		682,563		$	4.34
Shares vested but not released		298,100		$	5.05

The fair value of the Company’s RSUs is calculated based upon the fair market value of the Company’s common stock at the date of grant. As of December 31, 2020, there was $2.5 million of unrecognized compensation cost related to unvested RSUs granted, which is expected to be recognized over a weighted average period of 2.1 years.

The Company granted 200,000 PSUs to a certain key employee during the year ended December 31, 2020, with a grant date fair value of $6.38 per share. No PSUs were granted during the year ended December 31, 2019. The PSUs are subject to the attainment of performance goals established by the Compensation Committee, the periods during which performance is to be measured, and other limitations and conditions. Performance goals are based on pre-established objectives that specify the manner of determining the number of PSUs that will be granted if performance goals are attained. If the employee terminates employment, their non-vested portion of the PSUs will not vest and all rights to the non-vested portion will terminate.

The following is a summary of PSU activity for the year ended December 31, 2020:

	Number Outstanding		Fair Value
Unvested as of December 31, 2019		—	$	—
Granted		200,000		6.38
Vested		—		—
Forfeited		—		—
Unvested as of December 31, 2020		200,000	$	6.38

As of December 31, 2020, there was $1.2 million of unrecognized compensation cost related to unvested PSUs, which is expected to be recognized over a period of 2.0 years. No tax benefit was realized from PSUs for the year ended December 31, 2020.

The following table summarizes stock-based compensation expense related to stock options, RSUs, and PSUs included in the consolidated statements of comprehensive loss for the years ended December 31, 2020 and 2019 (in thousands):

	Year Ended December 31,
	2020		2019
Cost of revenue	$	160	$	128
Research and development		685		651
Selling and marketing		480		595
General and administrative		1,702		1,276
Total	$	3,027	$	2,650

During the years ended December 31, 2020 and 2019, the Company repurchased 171,641 and 175,878 shares, respectively, of common stock surrendered to the Company to satisfy tax withholding obligations in connection with the vesting of RSUs issued to employees.