Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Net operating loss carryforwards	$ 5,310,628	$ 7,547,296
Stock option compensation	2,141,973	2,720,186
Orphan Drug credits	2,537,039	1,218,069
Capitalized start-up costs and other	5,247,469	4,690,843
Valuation allowance	(15,237,109)	(16,176,394)
Net deferred tax asset
Intangible assets	(2,223,678)	(3,279,363)
Net deferred tax liability	$ (2,223,678)	$ (3,279,363)