Details of Certain Financial Statement Components - Property, plant and equipment, net (Details) - USD ($)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Property, plant and equipment, net
Property, plant and equipment, gross	$ 2,771,000		$ 2,770,000
Less: accumulated depreciation	(2,349,000)		(2,296,000)
Total property, plant and equipment, net	422,000		474,000
Depreciation expense	47,000	$ 47,000
Furniture, machinery and equipment
Property, plant and equipment, net
Property, plant and equipment, gross	2,241,000		2,243,000
Leasehold improvements
Property, plant and equipment, net
Property, plant and equipment, gross	$ 530,000		$ 527,000