Stock-Based Compensation Plan (Tables)

9 Months Ended

Sep. 30, 2023

Stock-Based Compensation Plan [Abstract]

Summary of weighted-average assumptions

	2023		2022
Risk-free interest rate	3.42	%	2.43	%
Expected volatility	129	%	127	%
Expected term in years	6.0		6.0
Dividend yield	—	%	—	%

Schedule of option activity under stock-based compensation plans

		Weighted-
		Average
		Exercise
	Options	Price
	(in thousands)
Outstanding at December 31, 2022	658	$	11.67
Granted	221	$	1.39
Expired	(11)	$	92.00
Outstanding at September 30, 2023	868	$	8.06
Vested and expected to vest September 30, 2023	849	$	8.15
Exercisable at September 30, 2023	458	$	12.44