Note 16 - Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Net operating loss carry-forwards	$ 6,924	$ 43,822
Research and development tax credits	1,591	3,357
Capitalized research and development	4,773	2,326
Sale of future royalties	7,486	8,383
Accruals, reserves and other	1,321	714
Total deferred tax assets	22,095	58,602
Valuation allowance	(13,365)	(48,626)
Deferred tax assets net of valuation allowance	8,730	9,976
Intangible assets	(8,730)	(9,976)
Total deferred tax liabilities	(8,730)	(9,976)
Net deferred tax assets