Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Fair Values of Stock Options Granted and Assumptions used in Black-Scholes Model

The estimated fair values of stock options granted, and the assumptions used for the Black-Scholes option pricing model were as follows:

	Nine Months Ended September 30,
	2022		2021
Estimated fair values of stock options granted	$	0.86	$	3.93
Assumptions:
Risk-free interest rate		1.9% - 3.5%		0.6% - 1.1%
Expected volatility		89.7% - 92.8%		80.1% - 82.0%
Expected term (in years)		5.50 - 6.89		5.5 - 6.5

Summary of Stock Option Activity

Information on stock option activity is as follows:

	Options Exercisable		Weighted- Average Exercise Price Per Share		Options Outstanding			Weighted- Average Exercise Price Per Share
Balance as of December 31, 2021		2,789,110	$	10.23		4,658,405		$	9.47
Granted						1,609,000			1.12
Exercised						—			—
Forfeited or expired						(420,606	)		7.05
Balance as of September 30, 2022		3,314,828	$	9.88		5,846,799		$	7.35

Summary of Stock-based Compensation Expense

Stock-based compensation expense related to PSUs is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
In Thousands	2022		2021		2022		2021
Stock-based compensation expense	$	171	$	122	$	478	$	(133	)

Schedule of Net Cash Proceeds from Exercise of Stock Options Less Shares Used for Minimum Withholding Taxes and Intrinsic Value of Options Exercised

Net cash proceeds from the exercise of stock options less shares used for minimum withholding taxes and the intrinsic value of options exercised were as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
In Thousands	2022		2021		2022		2021
Net cash proceeds	$	—	$	—	$	—	$	227
Intrinsic value of options exercised	$	—	$	—	$	—	$	344

Summary of Activity of Restricted Stock Units

Information on restricted stock unit activity is as follows:

	Number of Restricted Stock Units Outstanding			Weighted- Average Grant Date Fair Value
Unvested balance as of December 31, 2021		571,303		$	6.15
Granted		1,077,600			1.26
Vested		(274,487	)		6.14
Forfeited		(113,955	)		4.13
Unvested balance as of September 30, 2022		1,260,461		$	2.15

Summary of Grant Date Fair Value of Restricted Stock Unit Awards Vested

The total grant-date fair value of restricted stock unit awards that vested is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
In Thousands	2022		2021		2022		2021
Grant-date fair value	$	530	$	581	$	1,686	$	1,223

Summary of Stock-Based Compensation Granted As Deemed Dividends

The Company accounts for stock-based compensation awards granted to employees of Cellectis as deemed dividends. The Company recorded deemed dividends as follows:

	Three Months Ended September 30,					Nine Months Ended September 30,
In Thousands	2022		2021			2022		2021
Deemed dividends from grants to Cellectis employees	$	18	$	(84	)	$	82	$	(55	)

Share-based Payment Arrangement, Performance Shares, Outstanding Activity

PSU activity for the nine months ended September 30, 2022, is as follows:

	Number of PSUs
Outstanding as of December 31, 2021:		745,000
Issued		530,000
Forfeited/canceled		(145,000	)
Exercised		—
Outstanding as of September 30, 2022:		1,130,000

Stock Options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock-based Compensation Expense

Stock-based compensation expense related to stock option awards is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
In Thousands	2022		2021		2022		2021
Stock-based compensation expense	$	530	$	698	$	1,420	$	1,103

Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock-based Compensation Expense

Stock-based compensation expense related to restricted stock units is as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
In Thousands	2022		2021		2022		2021
Stock-based compensation expense	$	334	$	416	$	992	$	(105	)