Note 8 - Concentrations
 12 Months Ended
Mar. 31, 2018
Notes to Financial Statements  
Concentration Risk Disclosure [Text Block]
NOTE
8.
CONCENTRATIONS

     The following table summarizes customers comprising
10%
or more of revenue for the
three
most recent fiscal years:
 
   
% of Revenue for Year
Ended March 31
  
   
2018
    
2017
    
2016
  
Customer A
    
19%
      
22%
      
23%
  
Customer B
    
18%
      
20%
      
20%
  
 
     These
two
customers accounted for
51%
of our accounts receivable as of
March 
31,
2018
and
40%
as of
March 
31,
2017.
We believe the receivable balances from these customers do
not
represent a significant credit risk based on past collection experience.

     Revenue by geographic region was as follows:
 
   
Year Ended March 31
  
   
2018
    
2017
    
2016
  
United States
   $
14,911,258
     $
13,600,236
     $
12,392,053
  
Europe, the Middle East, and Africa
    
10,133,134
      
9,612,883
      
11,392,046
  
Asia-Pacific
    
4,607,811
      
4,200,934
      
3,113,484
  
Rest of World
    
211,678
      
912,143
      
819,695
  
Total Revenue
   $
29,863,881
     $
28,326,196
     $
27,717,278