Balance Sheet Components - Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Land, Property and Equipment
Total property and equipment at cost	$ 961,000	$ 961,000
Accumulated depreciation	(465,000)	(404,000)
Property and equipment, net	496,000	557,000
Depreciation and amortization expense	61,000	171,000
Land
Land, Property and Equipment
Total property and equipment at cost	396,000	396,000
Lab equipment
Land, Property and Equipment
Total property and equipment at cost	477,000	477,000
Software
Land, Property and Equipment
Total property and equipment at cost	63,000	63,000
Furniture and fixtures
Land, Property and Equipment
Total property and equipment at cost	18,000	18,000
Computers and peripherals
Land, Property and Equipment
Total property and equipment at cost	$ 7,000	$ 7,000