Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2022

Stock-Based Compensation

Schedule of stock-based compensation expense attributable to share-based payments made to employees and directors and included in operating expenses

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(in thousands)	2022		2021		2022		2021
Stock-based compensation:
Research and development
Employee Stock Purchase Plan	$	6	$	7	$	21	$	22
Equity Incentive Plan		53		51		194		469
	$	59	$	58	$	215	$	491
General and administrative
Employee Stock Purchase Plan	$	2	$	—	$	5	$	3
Equity Incentive Plan		350		417		1,298		1,496
	$	352	$	417	$	1,303	$	1,499
Total stock-based compensation expense	$	411	$	475	$	1,518	$	1,990

Schedule of weighted average assumptions applied to options

	2022		2021
Average risk-free interest rate		2.6%		0.4%
Expected dividend yield		—		—
Expected lives (years)		3.8		3.6
Expected volatility		104%		94%
Weighted average exercise price (per share)	$	0.49	$	2.68

Schedule of information related to outstanding and exercisable options

($ in thousands, except per share data)	Common Stock Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
Outstanding at December 31, 2021	5,202,006	$	8.06	5.9	$	2,949
Granted	1,169,800		0.49
Exercised	—		—
Forfeited	—		—
Expired	(588,038)		2.87
Options assumed in connection with Aceragen Acquisition	1,887,860		4.15	9.3
Outstanding at September 30, 2022	7,671,628	$	6.34	7.3	$	—
Exercisable at September 30, 2022	4,218,823	$	9.29	5.7	$	—
	Preferred Stock Options	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021	—	$	—	—		—
Options assumed in connection with Aceragen Acquisition	19,826		394.82	9.3
Outstanding at September 30, 2022	19,826	$	394.82	9.3	$	—
Exercisable at September 30, 2022	2,187	$	142.05	8.9	$	—

Schedule of information related to restricted stock activity

	Time-based Awards			Market/Performance-based Awards
($ in thousands, except per share data)	Number of Shares	Weighted-Average Grant Date Fair Value		Number of Shares	Weighted-Average Grant Date Fair Value
Nonvested shares at December 31, 2021	68,675	$	2.30	507,028	$	1.54
Granted	283,207		0.40	—		—
Cancelled	—		—	—		—
Vested	(27,212)		2.43	—		—
Nonvested shares at September 30, 2022	324,670	$	0.63	507,028	$	1.54