v3.19.3
Note 10 - Income Taxes (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Income Tax Expense (Benefit), Total $ 0 $ 0
Deferred Income Tax Assets, Net, Total 0  
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount $ 1,200,000 (964,000)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00%  
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability, Total   $ 0
Number of Foreign Subsidiaries 0  
Operating Loss Carryforwards, Total $ 33,500,000  
Operating Lease Carryforwards with Expiration Dates 28,700,000  
Operating Loss Carryforwards Expiring Indefinitely 4,800,000  
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total $ 0  
Domestic Tax Authority [Member]    
Open Tax Year 2014 2015 2016 2017 2018  
Research Tax Credit Carryforward [Member] | Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]    
Tax Credit Carryforward, Amount $ 1,800,000  
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member]    
Tax Credit Carryforward, Amount $ 700,000  
Earliest Tax Year [Member]    
Operating Loss Carryforwards, Expiration Date Dec. 31, 2033  
Earliest Tax Year [Member] | Research Tax Credit Carryforward [Member] | Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]    
Tax Credit Carryforward, Expiration Date Dec. 31, 2031