Note 12 - Stock-based Compensation (Tables)
   | 
9 Months Ended | 
Dec. 31, 2023  | 
| Notes Tables | 
 
 | 
| Share-Based Payment Arrangement, Option, Activity [Table Text Block] | 
    
|   | 
  | 
  Nine-Month Periods Ended   | 
  | 
 
|   | 
  | 
  December 31, 2023   | 
  | 
  | 
  January 1, 2023   | 
  | 
 
|   | 
  | 
  Weighted-   | 
  | 
  | 
  | 
  | 
  | 
  | 
  Weighted-   | 
  | 
  | 
  | 
  | 
  | 
 
|   | 
  | 
  Average   | 
  | 
  | 
  Number of   | 
  | 
  | 
  Average   | 
  | 
  | 
  Number of   | 
  | 
 
|   | 
  | 
  Exercise   | 
  | 
  | 
  Options   | 
  | 
  | 
  Exercise   | 
  | 
  | 
  Options   | 
  | 
 
|   | 
  | 
  Price   | 
  | 
  | 
  Outstanding   | 
  | 
  | 
  Price   | 
  | 
  | 
  Outstanding   | 
  | 
 
|   Outstanding at Beginning of Period   | 
  | 
$ | 
7.32 | 
  | 
  | 
  | 
735,500 | 
  | 
  | 
$ | 
7.39 | 
  | 
  | 
  | 
635,500 | 
  | 
 
|   Granted   | 
  | 
  | 
5.18 | 
  | 
  | 
  | 
130,000 | 
  | 
  | 
  | 
6.54 | 
  | 
  | 
  | 
120,000 | 
  | 
 
|   Exercised   | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
4.92 | 
  | 
  | 
  | 
(20,000 | 
) | 
 
|   Expired   | 
  | 
  | 
6.14 | 
  | 
  | 
  | 
(10,000 | 
) | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
 
|   Outstanding at End of Period   | 
  | 
  | 
7.01 | 
  | 
  | 
  | 
855,500 | 
  | 
  | 
  | 
7.32 | 
  | 
  | 
  | 
735,500 | 
  | 
 
|   Exercisable at End of Period   | 
  | 
  | 
7.41 | 
  | 
  | 
  | 
665,500 | 
  | 
  | 
  | 
7.42 | 
  | 
  | 
  | 
499,000 | 
  | 
 
 
   
 | 
| Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] | 
    
|   | 
  | 
  Nine-Month Periods Ended   | 
  | 
 
|   | 
  | 
  December 31, 2023   | 
  | 
  | 
  January 1, 2023   | 
  | 
 
|   Number of options issued   | 
  | 
  | 
10,000 | 
  | 
  | 
  | 
120,000 | 
  | 
  | 
  | 
120,000 | 
  | 
 
|   Grant date   | 
  | 
  November 14, 2023   | 
  | 
  | 
  June 21, 2023   | 
  | 
  | 
  June 7, 2022   | 
  | 
 
|   Dividend yield   | 
  | 
  | 
7.60 | 
% | 
  | 
  | 
6.08 | 
% | 
  | 
  | 
4.89 | 
% | 
 
|   Expected volatility   | 
  | 
  | 
20.00 | 
% | 
  | 
  | 
25.00 | 
% | 
  | 
  | 
30.00 | 
% | 
 
|   Risk free interest rate   | 
  | 
  | 
4.56 | 
% | 
  | 
  | 
4.29 | 
% | 
  | 
  | 
2.95 | 
% | 
 
|   Contractual term (years)   | 
  | 
  | 
10.00 | 
  | 
  | 
  | 
10.00 | 
  | 
  | 
  | 
10.00 | 
  | 
 
|   Expected term (years)   | 
  | 
  | 
3.00 | 
  | 
  | 
  | 
3.00 | 
  | 
  | 
  | 
4.00 | 
  | 
 
|   Forfeiture rate   | 
  | 
  | 
5.00 | 
% | 
  | 
  | 
5.00 | 
% | 
  | 
  | 
5.00 | 
% | 
 
|   Exercise price (grant-date closing price) per option   | 
  | 
$ | 
4.21 | 
  | 
  | 
$ | 
5.26 | 
  | 
  | 
$ | 
6.54 | 
  | 
 
|   Fair value per option   | 
  | 
$ | 
0.20 | 
  | 
  | 
$ | 
0.46 | 
  | 
  | 
$ | 
0.90 | 
  | 
 
 
   
 | 
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] | 
    
|   | 
  | 
  Three-Month Period Ended December 31, 2023   | 
  | 
  | 
  Three-Month Period Ended January 1, 2023   | 
  | 
 
|   | 
  | 
  Cost of   | 
  | 
  | 
  Marketing &   | 
  | 
  | 
  | 
  | 
  | 
  | 
  Cost of   | 
  | 
  | 
  Marketing &   | 
  | 
  | 
  | 
  | 
  | 
 
|   | 
  | 
  Products   | 
  | 
  | 
  Administrative   | 
  | 
  | 
  Total   | 
  | 
  | 
  Products   | 
  | 
  | 
  Administrative   | 
  | 
  | 
  Total   | 
  | 
 
|   Options Granted in Fiscal Year   | 
  | 
  Sold   | 
  | 
  | 
  Expenses   | 
  | 
  | 
  Expense   | 
  | 
  | 
  Sold   | 
  | 
  | 
  Expenses   | 
  | 
  | 
  Expense   | 
  | 
 
|   2021   | 
  | 
$ | 
- | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
11 | 
  | 
  | 
$ | 
11 | 
  | 
 
|   2022   | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
9 | 
  | 
  | 
  | 
20 | 
  | 
  | 
  | 
29 | 
  | 
 
|   2023   | 
  | 
  | 
5 | 
  | 
  | 
  | 
7 | 
  | 
  | 
  | 
12 | 
  | 
  | 
  | 
6 | 
  | 
  | 
  | 
7 | 
  | 
  | 
  | 
13 | 
  | 
 
|   2024   | 
  | 
  | 
3 | 
  | 
  | 
  | 
4 | 
  | 
  | 
  | 
7 | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
 
|   | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
 
|   Total stock option compensation   | 
  | 
$ | 
8 | 
  | 
  | 
$ | 
11 | 
  | 
  | 
$ | 
19 | 
  | 
  | 
$ | 
15 | 
  | 
  | 
$ | 
38 | 
  | 
  | 
$ | 
53 | 
  | 
 
 
    
|   | 
  | 
  Nine-Month Period Ended December 31, 2023   | 
  | 
  | 
  Nine-Month Period Ended January 1, 2023   | 
  | 
 
|   | 
  | 
  Cost of   | 
  | 
  | 
  Marketing &   | 
  | 
  | 
  | 
  | 
  | 
  | 
  Cost of   | 
  | 
  | 
  Marketing &   | 
  | 
  | 
  | 
  | 
  | 
 
|   | 
  | 
  Products   | 
  | 
  | 
  Administrative   | 
  | 
  | 
  Total   | 
  | 
  | 
  Products   | 
  | 
  | 
  Administrative   | 
  | 
  | 
  Total   | 
  | 
 
|   Options Granted in Fiscal Year   | 
  | 
  Sold   | 
  | 
  | 
  Expenses   | 
  | 
  | 
  Expense   | 
  | 
  | 
  Sold   | 
  | 
  | 
  Expenses   | 
  | 
  | 
  Expense   | 
  | 
 
|   2021   | 
  | 
$ | 
- | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
3 | 
  | 
  | 
$ | 
37 | 
  | 
  | 
$ | 
40 | 
  | 
 
|   2022   | 
  | 
  | 
10 | 
  | 
  | 
  | 
21 | 
  | 
  | 
  | 
31 | 
  | 
  | 
  | 
31 | 
  | 
  | 
  | 
66 | 
  | 
  | 
  | 
97 | 
  | 
 
|   2023   | 
  | 
  | 
17 | 
  | 
  | 
  | 
24 | 
  | 
  | 
  | 
41 | 
  | 
  | 
  | 
12 | 
  | 
  | 
  | 
17 | 
  | 
  | 
  | 
29 | 
  | 
 
|   2024   | 
  | 
  | 
6 | 
  | 
  | 
  | 
8 | 
  | 
  | 
  | 
14 | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
- | 
  | 
 
|   | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
 
|   Total stock option compensation   | 
  | 
$ | 
33 | 
  | 
  | 
$ | 
53 | 
  | 
  | 
$ | 
86 | 
  | 
  | 
$ | 
46 | 
  | 
  | 
$ | 
120 | 
  | 
  | 
$ | 
166 | 
  | 
 
 
    
|   | 
  | 
  Three-Month Periods Ended   | 
  | 
  | 
  Nine-Month Periods Ended   | 
  | 
 
|   Stock Granted in Fiscal Year   | 
  | 
  December 31, 2023   | 
  | 
  | 
  January 1, 2023   | 
  | 
  | 
  December 31, 2023   | 
  | 
  | 
  January 1, 2023   | 
  | 
 
|   2021   | 
  | 
$ | 
- | 
  | 
  | 
$ | 
9 | 
  | 
  | 
$ | 
- | 
  | 
  | 
$ | 
76 | 
  | 
 
|   2022   | 
  | 
  | 
37 | 
  | 
  | 
  | 
113 | 
  | 
  | 
  | 
147 | 
  | 
  | 
  | 
472 | 
  | 
 
|   2023   | 
  | 
  | 
23 | 
  | 
  | 
  | 
78 | 
  | 
  | 
  | 
160 | 
  | 
  | 
  | 
130 | 
  | 
 
|   2024   | 
  | 
  | 
111 | 
  | 
  | 
  | 
- | 
  | 
  | 
  | 
180 | 
  | 
  | 
  | 
- | 
  | 
 
|   | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
 
|   Total stock grant compensation   | 
  | 
$ | 
171 | 
  | 
  | 
$ | 
200 | 
  | 
  | 
$ | 
487 | 
  | 
  | 
$ | 
678 | 
  | 
 
 
   
 | 
| Schedule of Nonvested Share Activity [Table Text Block] | 
    
|   Number of Shares   | 
  | 
  | 
  Fair Value per Share   | 
  | 
  Grant Date   | 
  | 
  Vesting Period (Years)   | 
 
| 60,412 | 
  | 
  | 
  | 
$4.85 | 
  | 
  August 15, 2023   | 
  | 
  One   | 
 
| 46,896 | 
  | 
  | 
  | 
6.65 | 
  | 
  August 16, 2022   | 
  | 
  One   | 
 
| 40,165 | 
  | 
  | 
  | 
7.47 | 
  | 
  August 11, 2021   | 
  | 
  One   | 
 
| 41,452 | 
  | 
  | 
  | 
5.79 | 
  | 
  August 12, 2020   | 
  | 
  Two   | 
 
 
    
|   Number of Shares   | 
  | 
  | 
  Fair Value per Share   | 
  | 
  Grant Date   | 
  | 
  Vesting Date   | 
 
| 26,000 | 
  | 
  | 
  | 
$4.77 | 
  | 
  August 14, 2023   | 
  | 
  August 14, 2024   | 
 
| 40,000 | 
  | 
  | 
  | 
5.85 | 
  | 
  March 21, 2023   | 
  | 
  March 21, 2025   | 
 
| 25,000 | 
  | 
  | 
  | 
7.98 | 
  | 
  June 9, 2021   | 
  | 
  June 9, 2022   | 
 
| 10,000 | 
  | 
  | 
  | 
7.60 | 
  | 
  February 22, 2021   | 
  | 
  February 22, 2023   | 
 
| 20,000 | 
  | 
  | 
  | 
4.92 | 
  | 
  June 10, 2020   | 
  | 
  June 10, 2022   | 
 
 
   
 |