
	Number of Stock Option Awards			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2021		2,300,819		$	14.12		9.55	$	976
Granted		1,427,285		$	12.80		9.75	$	—
Forfeited		(40,290	)	$	17.08
Balance at June 30, 2022		3,687,814		$	13.57		9.33	$	1,079
Exercisable at June 30, 2022		596,276		$	12.93		9.09	$	315
Nonvested at June 30, 2022		3,091,538		$	13.70		9.37	$	764

As of June 30, 2022, there was $27.7 million of unrecognized equity-based compensation expense related to stock options which is expected to be recognized over a weighted-average period of approximately 2.9 years.

A summary of RSU activity during the periods indicated is as follows:


	Number of Restricted Stock Units			Weighted Average Grant-Date Fair Value per Share
Balance at December 31, 2021		596,500		$	19.56
Granted		443,400		$	13.21
Forfeited		(69,800	)	$	18.20
Balance at June 30, 2022		970,100		$	16.76

As of June 30, 2022, there was $11.6 million of unrecognized equity-based compensation expense related to RSUs which is expected to be recognized over a weighted-average period of approximately 2.3 years.


	Number of Restricted Stock Awards			Weighted Average Grant-Date Fair Value per Share
Balance at December 31, 2021		113,173		$	6.15
Vested		(25,170	)	$	6.16
Forfeited		(2,374	)	$	6.36
Balance at June 30, 2022		85,629		$	6.14

As of June 30, 2022, there was $0.2 million of unrecognized equity-based compensation expense related to RSAs which is expected to be recognized over a weighted-average period of approximately 1.3 years. The total fair value of the RSAs that vested in 2022 was approximately $0.4 million.

The Company recognized stock-based compensation expense related to the 2021 Employee Stock Purchase Plan (the “ESPP”) that was not significant during the three and six months ended June 30, 2022. There was no stock-based compensation expense related to the ESPP recognized during the three and six months ended June 30, 2021. As of June 30, 2022, contributions withheld from employees were not significant and recorded as a component of accrued expenses in the condensed consolidated balance sheet. As of June 30, 2022, total unrecognized compensation costs related to the ESPP was $0.1 million, which will be amortized over a weighted average vesting term of 0.4 years.

The following table summarizes the components of equity-based compensation expense resulting from the grant of stock options, RSUs, RSAs, the ESPP, and a secondary sales transaction entered into in February 2021, recorded in the Company’s condensed consolidated statement of operations and comprehensive loss (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	1,638		61	$	2,886	$	287
General and administrative		2,338		221		3,995		448
Total equity-based compensation	$	3,976		282	$	6,881	$	735