Annual report pursuant to Section 13 and 15(d)

Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual)

v3.20.1
Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual)
12 Months Ended
Apr. 26, 2019
$ / shares
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Jun. 18, 2019
shares
Apr. 25, 2019
shares
Jan. 01, 2019
USD ($)
Mar. 11, 2015
USD ($)
Common Stock, Par or Stated Value Per Share | $ / shares $ 0.001 $ 0.001 $ 0.001        
Common Stock, Shares, Outstanding, Ending Balance | shares 10,100,000 19,234,960 10,019,535        
Common Stock, Shares Authorized | shares 300,000,000 300,000,000 300,000,000        
Notes Payable, Fair Value Disclosure   $ 306,000 $ 316,000        
Derivative Liability, Total   0 63,000       $ 63,000
Patent and Trademark Costs   56,700 0        
Previously Capitalized Patent Costs Abandoned   58,000 0        
Impairment of Long-Lived Assets to be Disposed of   0 0        
Unrecognized Tax Benefits, Ending Balance   $ 0 0        
Open Tax Year   2016 2017 2018 2019          
Operating Lease, Right-of-Use Asset   $ 281,688     $ 406,842  
Accounting Standards Update 2016-02 [Member]              
Operating Lease, Right-of-Use Asset   $ 407,000       $ 407,000  
Minimum [Member]              
Finite-Lived Intangible Asset, Useful Life   5 years          
Maximum [Member]              
Finite-Lived Intangible Asset, Useful Life   15 years          
The 2002 Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | shares   12,000,000          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   0          
The 2014 Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | shares   15,000,000          
The 2002 and 2014 Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period   10 years          
The 2002 and 2014 Plan [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   1 year          
The 2002 and 2014 Plan [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   4 years          
Underwriting Agreement Warrants [Member]              
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares       600,000      
Class of Warrant or Right Percent of Common Stock Sold       7.50%      
Warrants and Rights Outstanding   $ 261,000          
Underwriting Agreement Warrants [Member] | Measurement Input, Price Volatility [Member]              
Warrants and Rights Outstanding, Measurement Input   88.6          
Underwriting Agreement Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]              
Warrants and Rights Outstanding, Measurement Input   1.8          
Underwriting Agreement Warrants [Member] | Measurement Input, Expected Dividend Payment [Member]              
Warrants and Rights Outstanding, Measurement Input   0          
Before Reverse Stock Split [Member]              
Common Stock, Shares, Outstanding, Ending Balance | shares         201,000,000    
Reverse Stock Split [Member]              
Stockholders' Equity Note, Stock Split, Conversion Ratio 20            
Navidea Biopharmaceuticals Limited [Member]              
Noncontrolling Interest, Ownership Percentage by Parent   100.00%          
Macrophage Therapeutics [Member]              
Noncontrolling Interest, Ownership Percentage by Parent   99.90%