Note 2 - Basis of Presentation, Principles of Consolidation, Significant Accounting Policies and Liquidity (Details Textual) $ in Thousands, shares in Millions		3 Months Ended
	Jan. 29, 2021	Mar. 31, 2022 USD ($) shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($)
Net Income (Loss) Attributable to Parent, Total		$ (6,867)	$ (4,445)
Net Cash Provided by (Used in) Operating Activities, Total		(4,805)	$ (3,624)
Retained Earnings (Accumulated Deficit), Total		(79,677)		$ (72,810)
Cash and Cash Equivalents, at Carrying Value, Total		$ 66,104		$ 70,903
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares		4.8	3.8
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	6