Note 10 - Income Taxes - Significant Components of the Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Stock-based compensation	$ 3,085,484	$ 922,463
Tax credit carryforwards	3,616,246
Net operating loss carryforwards	8,715,591	833,458
Intangible assets	372,944	604,416
Other	350,690	81,111
Total deferred tax assets	16,140,955	2,441,448
Deferred tax liabilities:
Property and equipment	8,922
Total deferred tax liabilities	8,922
Net deferred tax assets	16,132,033	2,441,448
Less valuation allowance	(16,132,033)	(2,441,448)
Total deferred tax assets (liabilities)