Stock Purchase Plans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Aug. 27, 2015
Stock Purchase Plans
Common shares issued for employee stock purchase plan	$ 50,000	$ 21,000
Options, outstanding (in shares)	1,097,000		1,000,000	3,000
Director compensation plan, expense	$ 62,000	$ 64,000
Non-Employee Director Compensation Plan
Stock Purchase Plans
Number of shares allowed to be purchased (in shares)	100,000
Maximum percentage of base compensation	100.00%
Current percentage of base compensation	50.00%
Options, outstanding (in shares)	48,036
Common shares issued for director compensation plan (in shares)	2,888	2,422
Director compensation plan, expense	$ 62,000	$ 64,000
Employee Stock
Stock Purchase Plans
Number of shares allowed to be purchased (in shares)	1,500,000
Purchase price of the shares with respect to market value (as a percent)	95.00%
Maximum percentage of base compensation	15.00%
Maximum market value	$ 25,000
Number of shares issued under the plan (in shares)	2,550	854