Note 2 - Supplemental Balance Sheet Information - Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Property and equipment, gross	$ 3,020	$ 2,956
Less accumulated depreciation	(2,739)	(2,294)
Property and equipment, net	$ 281	662
Equipment [Member]
Estimated useful life (Year)	5 years
Property and equipment, gross	$ 144	144
Leasehold Improvements [Member]
Property and equipment, gross	$ 725	725
Leasehold Improvements [Member] \| Minimum [Member]
Estimated useful life (Year)	2 years
Leasehold Improvements [Member] \| Maximum [Member]
Estimated useful life (Year)	5 years
Furniture and Fixtures [Member]
Estimated useful life (Year)	7 years
Property and equipment, gross	$ 16	16
Software and Software Development Costs [Member]
Estimated useful life (Year)	3 years
Property and equipment, gross	$ 2,135	$ 2,071

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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