Note 2 - Available-for-sale Securities (Tables)
 3 Months Ended
Mar. 31, 2018
Notes Tables  
Available-for-sale Securities [Table Text Block]
   
 
    
Gross
    
Gross
          
   
Amortized
    
Unrealized
    
Unrealized
      
 
  
   
Cost
    
Gains
    
Losses
    
Fair Value
  
                                 
March 31, 2018
  
 
 
 
  
 
 
 
  
 
 
 
  
 
 
 
Available-for-sale securities
                                
Mortgage-backed securities
  
$
23,238,466
   
$
6,317
   
$
(589,070
)
  
$
22,655,713
 
U.S. Government agencies
  
 
1,851,214
   
 
-
   
 
(70,878
)
  
 
1,780,336
 
Municipal obligations
  
 
1,661,224
   
 
761
   
 
(2,374
)
  
 
1,659,611
 
                                 
   
$
26,750,904
   
$
7,078
   
$
(662,322
)
  
$
26,095,660
 
                                 
December 31, 2017
                                
Available-for-sale securities
                                
Mortgage-backed securities
   $
21,028,794
     $
12,757
     $
(272,959
 )   $
20,768,592
  
U.S. Government agencies
    
2,006,786
      
44
      
(49,047
 )    
1,957,783
  
Municipal obligations
    
1,672,277
      
2,584
      
(1,355
 )    
1,673,506
  
                                 
    $
24,707,857
     $
15,385
     $
(323,361
 )   $
24,399,881
  
Available-for-sale Securities Debt Maturities [Table Text Block]
   
March 31, 2018
  
   
Amortized
    
Fair
  
   
Cost
    
Value
  
                 
Due in one year or less
  
 
1,246,805
   
 
1,247,484
 
Due after one to five years
  
 
23,707,371
   
 
23,120,803
 
Due after five to ten years
  
 
1,796,728
   
 
1,727,373
 
Due after ten years
  
 
-
   
 
-
 
                 
Totals
  
$
26,750,904
   
$
26,095,660
 
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block]
   
March 31, 2018
  
   
Less Than 12 Months
    
12 Months or More
    
Total
  
           
Gross
            
Gross
            
Gross
  
Description of
    
 
    
Unrealized
      
 
    
Unrealized
      
 
    
Unrealized
  
Securities
  
Fair Value
    
Losses
    
Fair Value
    
Losses
    
Fair Value
    
Losses
  
                                                 
Available-for-sale securities:
                                                
Mortgage-backed securities
  
$
12,464,292
   
$
(227,176
)
  
$
9,657,488
   
$
(361,894
)
  
$
22,121,780
   
$
(589,070
)
U.S. Government agencies
  
 
360,605
   
 
(5,948
)
  
 
1,419,731
   
 
(64,930
)
  
 
1,780,336
   
 
(70,878
)
Municipal obligations
  
 
663,256
   
 
(2,374
)
  
 
-
   
 
-
   
 
663,256
   
 
(2,374
)
                                                 
Total temporarily impaired securities
  
$
13,488,153
   
$
(235,498
)
  
$
11,077,219
   
$
(426,824
)
  
$
24,565,372
   
$
(662,322
)
   
December 31, 2017
  
   
Less Than 12 Months
    
12 Months or More
    
Total
  
           
Gross
            
Gross
            
Gross
  
Description of
    
 
    
Unrealized
      
 
    
Unrealized
      
 
    
Unrealized
  
Securities
  
Fair Value
    
Losses
    
Fair Value
    
Losses
    
Fair Value
    
Losses
  
                                                 
Available-for-sale securities:
                                                
Mortgage-backed securities
   $
3,468,607
     $
(39,099
 )   $
9,763,879
     $
(233,860
 )   $
13,232,486
     $
(272,959
 )
U.S. Government agencies
    
-
      
-
      
1,548,481
      
(49,047
 )    
1,548,481
      
(49,047
 )
Municipal obligations
    
416,600
      
(1,355
 )    
-
      
-
      
416,600
      
(1,355
 )
                                                 
Total temporarily impaired securities
   $
3,885,207
     $
(40,454
 )   $
11,312,360
     $
(282,907
 )   $
15,197,567
     $
(323,361
 )