Stock-based compensation expense was allocated as follows:


	Years Ended December 31,
	2023		2022
	(in thousands)
Cost of revenues	$	307	$	481
Sales and marketing		502		596
Research and development		825		996
General and administrative		1,372		1,482
	$	3,006	$	3,555

For stock-based awards granted by the Company, stock-based compensation cost is measured as of the grant date based on the fair value of the award and is subsequently expensed over the requisite service period. Stock-based compensation capitalized as internally developed software was $99 and $113 for 2023 and 2022, respectively.

The Company may grant, or has granted, stock options, restricted stock awards, stock appreciation rights, RSUs, performance awards and stock bonuses under the following equity incentive plans:

In April 2006, the Company’s Board of Directors (the “Board”) adopted and the stockholders approved the 2006 Stock Option Plan (“2006 Plan”), which provided for the grant of incentive and non-statutory stock options.

In February 2013 the Board adopted and the stockholders approved the 2013 Equity Incentive Plan (“2013 Plan”), which became effective on March 21, 2013. At that time, the Company ceased to grant equity awards under the 2006 Plan. Under the 2013 Plan, 643 shares of common stock were originally reserved for issuance. Additionally, all reserved and unissued shares under the 2006 Plan were eligible for issuance under the 2013 Plan. The 2013 Plan authorized the award of incentive and non-statutory stock options, restricted stock awards, stock appreciation rights, RSUs, performance awards and stock bonuses to the Company’s employees, directors, consultants, independent contractors and advisors. On January 1 of each calendar year through 2023, the number of shares of common stock reserved under the 2013 Plan automatically increased by an amount equal to 5% of the total outstanding shares as of the immediately preceding December 31, or such lesser number of shares as determined by the Board. Pursuant to terms of the 2013 Plan, the shares available for issuance increased by 861 shares of common stock on January 1, 2023. The 2013 Plan has expired in accordance with its terms and the Company has ceased granting awards under this plan.

On March 24, 2023, the Board approved the Amended and Restated 2013 Equity Incentive Plan ("Amended and Restated Plan") under which incentive and non-statutory stock options, restricted stock awards, stock appreciation rights, RSUs, performance awards and stock bonuses may be awarded to the Company’s employees, directors, consultants, independent contractors and advisors. Under the Amended and Restated Plan, 425 shares of common stock have been reserved for issuance. Additionally, shares that cease to be subject to equity awards that have been granted under the 2006 Plan and the 2013 Plan are eligible for issuance under the Amended and Restated Plan. On January 1 of each calendar year through 2033, the number of shares of common stock reserved under the Amended and Restated Plan will automatically increase by an amount equal to 5% of the total outstanding shares as of the immediately preceding December 31, or such lesser number of shares as determined by the Board. The Company's stockholders approved the Amended and Restated Plan at the Company's 2023 annual stockholder meeting on May 25, 2023.

Under the 2006 Plan, the 2013 Plan and the Amended and Restated Plan, the term of options granted may not exceed ten years. Unless the terms of an optionee's stock option agreement provide otherwise, if an optionee's service relationship with the Company, or any of its affiliates, ceases for any reason other than disability or death, the optionee may exercise the vested portion of any options for three months after the date of such termination. If an optionee's service relationship with the Company, or any of its affiliates, ceases due to disability or death (or an optionee dies within a certain period following cessation of service), the optionee or a beneficiary may exercise any vested options for a period of 12 months. In no event, however, may an option be exercised beyond the expiration of its term.

A summary of stock option activity under the 2006 Plan and the 2013 Plan is as follows:


	Options Outstanding
	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contract Term (in Years)		Aggregate Intrinsic Value
Balance at December 31, 2021		383		$	23.23		4.85	$	—
Options forfeited and cancelled		(46	)		49.87		—
Balance at December 31, 2022		337		$	19.59		4.45	$	—
Options forfeited and cancelled		(16	)		76.91		—
Balance at December 31, 2023		321		$	16.78		3.63	$	—
Options exercisable as of December 31, 2023		321		$	16.78		3.63
Options vested as of December 31, 2023		321			16.78		3.63
Options vested and expected to vest as of December 31, 2023		321			16.78		3.63

There were no grants or exercises of stock options in 2023 or 2022. As of December 31, 2023, there was no unrecognized compensation cost related to options. The total estimated fair value of options vested was $31 during 2023 and 2022, respectively.

A summary of RSU activity under the 2013 Plan and Amended and Restated Plan is as follows:


	RSUs Outstanding
	Number of Shares			Weighted Average Grant Date Fair Value Per Unit
Granted and unvested at December 31, 2021		1,542		$	4.60
RSUs granted		1,142			1.90
RSUs vested		(594	)		3.72
RSUs cancelled and withheld to cover taxes		(276	)		5.91
Granted and unvested at December 31, 2022		1,814		$	2.99
RSUs granted		1,482			1.23
RSUs vested		(825	)		2.97
RSUs cancelled and withheld to cover taxes		(746	)		2.99
Granted and unvested at December 31, 2023		1,725		$	1.48

As of December 31, 2023, there was $1,431 of unrecognized compensation cost related to RSUs, which is expected to be recognized over a weighted-average period of 1.2 years. The Company uses the fair market value of the underlying common stock on the dates of grant to determine the fair value of RSUs.

In February 2013, the Board and stockholders approved the 2013 Employee Stock Purchase Plan (“2013 ESPP”), under which 143 shares of common stock were originally reserved for issuance. The 2013 ESPP became effective on March 22, 2013. The 2013 ESPP generally provides for six-month purchase periods ending in May and November and the purchase price for shares of common stock purchased under the 2013 ESPP is 85% of the lesser of the fair market value of the common stock on (1) the first trading day of the applicable offering period and (2) the last trading day of each purchase period in the applicable offering period. On January 1 of each calendar year following the first offering date, the number of shares reserved under the 2013 ESPP automatically increased by an amount equal to 1% of the total outstanding shares as of immediately preceding December 31, but not to exceed 100 shares. Pursuant to terms of the 2013 ESPP, the shares available for issuance increased by 100 shares on January 1, 2023. The 2013 ESPP has expired in accordance with its terms.

On March 24, 2023, the Board approved the Amended and Restated 2013 Employee Stock Purchase Plan ("Amended and Restated ESPP") which provides for six-month purchase periods ending in May and November of each year with the purchase price for each share of common stock purchased being 85% of the lesser of the fair market value of the common stock on (1) the first trading day of the applicable offering period and (2) the last trading day of each purchase period in the applicable offering period. Under the Amended and Restated ESPP, 432 shares of common stock have been reserved for issuance. The Company's stockholders approved the Amended and Restated ESPP at the Company's 2023 annual stockholder meeting on May 25, 2023.

The Company estimates the fair value of purchase rights under the 2013 ESPP and Amended and Restated ESPP using the Black-Scholes valuation model. The fair value of each purchase right under the 2013 ESPP and Amended and Restated ESPP is estimated on the date of grant using the Black-Scholes option valuation model and the straight-line attribution approach with assumptions substantially similar to those used for the valuation of stock option awards, with the exception of the expected life. The expected life is estimated to be six months, which is consistent with the purchase periods under the 2013 ESPP and Amended and Restated ESPP.