Note 2 - Basis of Presentation, Principles of Consolidation and Significant Accounting Policies (Details Textual) $ in Thousands, shares in Millions		12 Months Ended
	Jan. 29, 2021	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares
Number of Operating Segments			1
Net Income (Loss) Attributable to Parent, Total		$ (15,894)	$ (17,355)
Net Cash Provided by (Used in) Operating Activities, Total		(18,951)	(17,771)
Retained Earnings (Accumulated Deficit), Ending Balance		(72,810)	(56,916)
Cash and Cash Equivalents, at Carrying Value, Ending Balance		70,903	$ 15,173
Impairment of Intangible Assets (Excluding Goodwill), Total		$ 0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares		4.3	3.6
Annamycin [Member]
Vendor Prepayments and Deposits, Expansion of Production Commitments		$ 0	$ 1,100
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	6