On December 19, 2019, the Company adopted the 2019 Incentive Award Plan (the “2019 Plan”) under which eligible employees, officers, directors and consultants of the Company may be granted incentive or non-qualified stock options, restricted stock, restricted stock units, or other stock-based awards, including shares of common stock. Pursuant to the 2019 Plan, the number of shares of Common Stock available for issuance under the 2019 Plan automatically increases on each January 1 until and including January 1, 2029, by an amount equal to the lesser of: (a) 5% of the shares of Common Stock outstanding on the final day of the immediately preceding calendar year and (b) such smaller number of shares as is determined by our Board of Directors (the “Board”). Our Board determined that the number of shares available for issuance under the 2019 Plan would increase by 2,126,451 as of January 1, 2021. The Compensation Committee did not increase the share reserve under the 2019 Plan in 2020. As of March 31, 2021, 9,626,451 shares of common stock, $0.0001 par value per share (the “Common Stock”) were reserved under the 2019 Plan, of which 4,330,506 shares of Common Stock remained available for issuance.

The following table summarizes the Company’s stock option activity under the 2019 Plan:

Description	Options Outstanding			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (1)
Options Outstanding, December 31, 2020		4,260,753		$	8.46		9.0	$	54
Granted		1,187,500			8.05
Exercised		(4,465	)		8.00
Forfeited		(146,366	)		8.19
Expired		(1,477	)		8.00
Options Outstanding, March 31, 2021		5,295,945		$	8.37		9.1	$	806
Options Vested and Exercisable, March 31, 2021		1,224,595		$	8.22		8.8	$	216
Options Vested and Expected to vest, March 31, 2021		5,295,945		$	8.37		9.1	$	806

(1)	Aggregate intrinsic value represents the difference between the estimated fair value of the underlying Common Stock (as defined below) and the exercise price of outstanding in-the-money options.

The following table summarizes additional information on stock option grants and vesting (in thousands):

Under the 2019 Plan, time-based vesting stock options generally vest over a three-year period, are subject to graded vesting schedules, and expire 10 years from the date of grant or within 90 days of termination. The weighted-average fair value per share of time-based vesting stock options granted by us was $1.79, and $2.19 during the three months ended March 31, 2021 and 2020, respectively.

Under the 2019 Plan, for the three months ended March 31, 2021 and 2020, the Company recognized $1.0 million and $0.8 million of stock-based compensation expense, respectively, in connection with time-based stock options, respectively. As of March 31, 2021, there was $7.0 million of unrecognized stock-based compensation expense related to unvested time-based stock options that are expected to be recognized over a weighted-average period of 2.0 years.

The Company used valuation models to value both time and performance-based vesting stock options granted during the three months ended March 31, 2021 and 2020. The following table summarizes the assumptions used in the valuation models to determine the fair value of awards granted to employees and non-employees under the 2019 Plan:

	Three Months Ended March 31, 2021		Three Months Ended March 31, 2020
Expected volatility	44.61%		37.63%
Expected term (in years)		6.00		6.00
Dividend yield	0.00%		0.00%
Risk-free interest rate	0.70%		1.43%

A discussion of management’s methodology for developing each of the assumptions used in the valuation model follows:

During the three months ended March 31, 2020, the Company granted to certain non-employee directors 50,000 restricted stock units (“RSUs”) for their initial appointment to the Board and for continued service, which are subject to a three or one-year vesting period. Accordingly, the Company will recognize the grant-date fair value of the stock awards, ratably over the vesting period. During the three months ended March 31, 2021, the Company recognized $0.2 million as stock-based compensation expense related to these grants.

Stock-based compensation expense is included in the Company’s Consolidated Statements of Comprehensive Loss within the following line items (in thousands):

	Three Months Ended March 31, 2021		Three Months Ended March 31, 2020
Cost of revenues	$	342	$	355
General and administrative		396		230
Research and development		64		73
Sales and marketing		176		167
Total	$	978	$	825

The Company granted RSUs to certain employees and board members which are subject to certain vesting criteria. The RSUs become eligible to begin vesting upon a liquidity event (as defined in the award agreements governing the RSUs). The amount and timing of the vesting of the RSUs is dependent on the type and timing of the liquidity event as it relates to the Business Combination date of December 19, 2019. Generally, a portion of the RSUs will first vest upon the occurrence of the liquidity event and the remainder will vest in installments thereafter, provided that if the liquidity event occurs after the third anniversary of the Business Combination, all RSUs will vest immediately upon the liquidity event. The vesting of the RSUs is generally subject to continued employment.

The following table summarizes the Company’s RSU activity under the 2019 Plan:

Description	RSUs Outstanding
Balance at December 31, 2020		1,290,432
Granted		308,750
Vested		(16,666	)
Forfeited		(51,190	)
Expired		-
Balance at March 31, 2021		1,531,326

The Company determined that the achievement of the liquidity event was not probable and therefore no expense was recorded during the three months ended March 31, 2021.