Note 5 - Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property and equipment, gross	$ 1,169	$ 1,138
Less: accumulated depreciation	(1,008)	(957)
Property and equipment, net	161	181
Computer Equipment and Software [Member]
Property and equipment, gross	157	132
Laboratory and Manufacturing Equipment [Member]
Property and equipment, gross	550	550
Furniture and Fixtures [Member]
Property and equipment, gross	59	55
Leasehold Improvements [Member]
Property and equipment, gross	332	332
Construction in Progress [Member]
Property and equipment, gross	$ 71	$ 69

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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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