Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows:

	Three Months Ended March 31,
	2022		2021
	(In thousands)
Research and development	$	1,792	$	2,230
General and administrative		3,497		4,785
Total	$	5,289	$	7,015

Assumptions Used in Applying Pricing Model

Key assumptions used to apply this pricing model were as follows:

	Three Months Ended March 31,
	2022			2021
Risk-free interest rate		2.1	%		0.4	%
Expected life of options	5.96 years			6.0 years
Expected volatility of underlying stock		72.8	%		70.5	%
Expected dividend yield		0.0	%		0.0	%

Summary of Stock Option Activity

The following is a summary of stock option activity for the three months ended March 31, 2022:

	Number of Options			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	(In thousands)					(In years)		(In thousands)
Outstanding at December 31, 2021		12,946		$	11.61
Granted		4,284			1.41
Exercised		-			-
Forfeited		(1,583	)		10.82
Outstanding at March 31, 2022		15,647		$	8.89		7.61	$	-
Exercisable at March 31, 2022		5,923		$	14.14		5.02	$	-

Summary of Service Based Restricted Stock Units

During the three months ended March 31, 2022, 87,500 RSUs were granted to an executive. The awards were service-based. Assuming all service conditions are achieved, 25% of the RSUs would vest annually for four years.

	Number of Service Based RSU Shares (in thousands)			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2021		2,222		$	8.70
Granted		88			1.41
Vested		(277	)		13.58
Forfeited		(345	)		7.98
Outstanding at March 31, 2022		1,688		$	7.67