In May 2021, the Company’s board of directors (the "Board") adopted, and its stockholders approved, the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective in connection with the IPO. The 2021 Plan provides for the grant of incentive stock options, within the meaning of Section 422 of the Internal Revenue Code ("IRC"), to the Company’s employees and any of its parent or subsidiary corporations’ employees, and for the grant of non-statutory stock options, restricted stock, restricted stock units, stock appreciation rights, and performance awards to the Company’s employees, directors and consultants and any of its parent or subsidiary corporations’ employees and consultants. A total of 10,459,000 shares of the Company’s Class A common stock have been reserved for issuance under the 2021 Plan in addition to (i) an annual increase of 4% of the outstanding shares of the Company's common stock, with Class A and Class B common stock taken together, on the first day of each fiscal year, subject to the Compensation Committee of the Board exercising discretion to increase or decrease such amount (the “Evergreen Addition”), and (ii) upon the expiration, forfeiture, cancellation, or reacquisition of any shares of Class B common stock underlying outstanding stock awards granted under the 2012 Equity Incentive Plan, an equal number of shares of Class A common stock, such number of shares not to exceed 7,563,990. On January 1, 2024, pursuant to the Evergreen Addition, approximately 5.0 million shares of Class A common stock were added to the 2021 Plan issuance reserve. At March 31, 2024, there were approximately 21.7 million remaining shares available for the Company to grant under the 2021 Plan.

A summary of the Company’s option activity during the three months ended March 31, 2024 was as follows (in thousands, except share and per share amounts):


						Weighted-
				Weighted-		Average
				Average		Remaining		Aggregate
	Options			Exercise Price		Contractual		Intrinsic
	Outstanding			per Share		Life (years)		Value
Outstanding at December 31, 2023		3,849,350		$	7.87		5.06	$	38,505
Options exercised		(67,746	)		1.44
Options forfeited		(1,333	)		8.66
Outstanding at March 31, 2024		3,780,271		$	7.98		4.85	$	55,817
Exercisable at March 31, 2024		3,732,980		$	7.97		4.83	$	55,161

No options were granted or expired during the three months ended March 31, 2024. Aggregate intrinsic value represents the difference between the exercise price of the options and the fair value of the Company’s common stock.

A summary of the Company’s RSU activity during the three months ended March 31, 2024 was as follows:


				Weighted-
				Average
	Number of			Grant Date
	RSUs Outstanding			Fair Value
Awarded and unvested at December 31, 2023		1,946,006		$	12.74
Awards granted		995,548			19.20
Awards vested		(235,619	)		11.42
Awards forfeited		(25,580	)		9.89
Awarded and unvested at March 31, 2024		2,680,355		$	15.28

The fair value of RSU grants is determined based upon the market closing price of the Company’s Class A common stock on the date of grant. RSUs vest over the requisite service period, which generally ranges between four years and five years from the date of grant for employees and one to three years for directors, subject to continued employment for employees and provision of services for nonemployees.

Stock-based compensation expense included in the condensed consolidated statements of operations was as follows:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Cost of revenue	$	51	$	45
Research and development		608		546
Sales and marketing		1,310		716
General and administrative		964		852
Total stock-based compensation	$	2,933	$	2,159

At March 31, 2024, there was $0.1 million of total unrecognized compensation cost related to unvested stock options granted under the 2012 Equity Incentive Plan, which is expected to be recognized over a remaining weighted-average period of 1.4 years.

At March 31, 2024, there was $38.5 million of total unrecognized compensation cost related to unvested RSUs granted under the 2021 Plan, which is expected to be recognized over a remaining weighted-average period of 3.8 years.