Stock-Based Compensation

9 Months Ended

Sep. 30, 2022

Share-Based Payment Arrangement [Abstract]

The Company recognized total stock-based compensation expense during the three and nine months ended September 30, 2022 and 2021 as follows (table in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Service-based awards:

Restricted stock units	$	46	$	81	$	84	$	263
Stock option awards	130		315		401		1,050
	176		396		485		1,313
Performance-based awards:
Restricted stock awards	—		—		(391)		(391)

Stock option awards	—		(35)		—		(364)
	—		(35)		(391)		(755)
Total	$	176	$	361	$	94	$	558

Performance Based Restricted Stock

A summary of the Company’s restricted stock awards during the nine months ended September 30, 2022 is as follows:


	Number of Shares	Weighted Average Grant-Date Fair Value
Unvested at January 1, 2022	7,118	$	62.70
Forfeited	(6,227)	$	62.70
Unvested at September 30, 2022	891	$	62.70

A summary of the Company’s restricted stock awards during the nine months ended September 30, 2021 is as follows:


	Number of Shares	Weighted Average Grant-Date Fair Value
Unvested at January 1, 2021	13,345	$	62.70
Forfeited	(6,227)	$	62.70
Unvested at September 30, 2021	7,118	$	62.70

The fair value of restricted stock awards are measured based on their fair value on the date of grant and amortized over the vesting period of 20 months. As of September 30, 2022, unvested restricted stock awards of 891 were related to performance-based awards. The forfeited performance-based restricted stock awards of 6,227 was due to the resignation of the Company's Chief Development Officer on March 25, 2022. These forfeited awards reduced stock-based compensation expense by $0.4 million. As of September 30, 2021, unvested restricted stock awards of 7,118 were related to performance-based awards. The forfeited performance-based restricted stock awards of 6,227 was due to the termination of the Company's former Chief Science Officer on January 19, 2021. These forfeited awards reduced stock-based compensation expense by $0.4 million.

Service-Based Restricted Stock Units

A summary of the Company’s service-based restricted stock units during the nine months ended September 30, 2022 is as follows:


	Number of Shares	Weighted Average Grant-Date Fair Value
Unvested at January 1, 2022	29,289	$	12.87
Granted	125,000	1.47
Vested	(23,515)	11.33
Forfeited	(5,774)	19.00
Unvested at September 30, 2022	125,000	$	1.47

A summary of the Company’s service-based restricted stock units during the nine months ended September 30, 2021 is as follows:


	Number of Shares	Weighted Average Grant-Date Fair Value
Unvested at January 1, 2021	24,136	$	28.60
Granted	28,186	9.90
Vested	(20,134)	26.18
Forfeited	(1,073)	52.91

Unvested at September 30, 2021	31,115	$	12.87

The fair value of service based restricted stock units are measured based on their fair value on the date of grant and amortized over the vesting period. The vesting periods range from 1 to 3 years. Stock-based compensation expense of $46,193 and $83,607 was recognized for the three and nine months ended September 30, 2022, respectively. Stock-based compensation expense of $0.1 million and $0.3 million was recognized for the three and nine months ended September 30, 2021, respectively. As of September 30, 2022, the unrecognized stock-based compensation expense was $0.1 million, which is expected to be recognized over an estimated weighted average remaining term of less than 1 year.

Service-Based Stock Options

The fair value of the service-based stock options granted for the nine months ended September 30, 2022 were based on the following assumptions:


			September 30, 2022
Exercise price			$1.28 - $1.66
Expected stock price volatility			76.2% - 78.5%
Risk-free interest rate			1.97% - 3.44%
Term (years)			5.5 - 6

A summary of the Company’s service-based stock option activity for the nine months ended September 30, 2022 is as follows:


	Shares Underlying Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at January 1, 2022	528,591	$	32.01	7.5	$	—
Granted	898,659	1.49		5.5	—

Forfeited	(30,093)	15.11		—	—
Expired	(85,466)	82.09		—	—
Outstanding at September 30, 2022	1,311,691	$	8.23	9.1	$	—

Exercisable at September 30, 2022	243,973	$	29.31	6.9	$	—

A summary of the Company’s service-based stock option activity for the nine months ended September 30, 2021 is as follows:


	Shares Underlying Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding at January 1, 2021	519,814	$	50.05	6.6	$	—
Granted	170,197	9.79		6.0	—
Forfeited	(35,025)	25.30		—	—
Expired	(121,202)	78.76		—	—
Outstanding at September 30, 2021	533,784	$	32.45	7.7	$	—

Exercisable at September 30, 2021	230,858	$	54.56	5.8	$	—

The aggregate intrinsic value in the table above is calculated as the difference between the closing price of the Company's common stock and the exercise price of the stock options that had strike prices below the closing price.

During the nine months ended September 30, 2022, the Company granted stock options to purchase up to 898,659 shares of common stock to certain employees. During the nine months ended September 30, 2022, 30,093 shares were forfeited and 85,466 shares expired. Forfeitures are recorded in the period of occurrence; compensation expense is adjusted accordingly.

Stock-based compensation expense recognized for service-based stock options was $0.1 million and $0.4 million for the three and nine months ended September 30, 2022, respectively. Stock-based compensation expense recognized for service-based stock options was $0.3 million and $1.0 million for the three and nine months ended September 30, 2021, respectively. As of September 30, 2022, total stock-based compensation expense related to unvested options not yet recognized totaled approximately $1.4 million, which is expected to be recognized over an estimated weighted average remaining term of 3.6 years.