Note 8 - Income Taxes (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (882,000)
Deferred Tax Assets, Valuation Allowance, Total	7,600,000
Operating Loss Carryforwards, Total	32,100,000
Income Taxes Paid, Net, Total	0	$ 0
Deferred Tax Assets, Net of Valuation Allowance, Total	$ 494,000	$ 0
Effective Income Tax Rate Reconciliation, Percent, Total	0.00%	0.00%