Balance Sheet Components - Property and Equipment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Land, Property and Equipment
Total property and equipment at cost	$ 961,000		$ 961,000		$ 961,000
Accumulated depreciation	(450,000)		(450,000)		(404,000)
Property and equipment, net	511,000		511,000		557,000
Depreciation and amortization expense	15,000	$ 15,000	46,000	$ 156,000
Land
Land, Property and Equipment
Total property and equipment at cost	396,000		396,000		396,000
Lab equipment
Land, Property and Equipment
Total property and equipment at cost	477,000		477,000		477,000
Software
Land, Property and Equipment
Total property and equipment at cost	63,000		63,000		63,000
Furniture and fixtures
Land, Property and Equipment
Total property and equipment at cost	18,000		18,000		18,000
Computers and peripherals
Land, Property and Equipment
Total property and equipment at cost	$ 7,000		$ 7,000		$ 7,000