Note A - Summary of Significant Accounting Policies (Tables)
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12 Months Ended | 
Sep. 30, 2015  | 
| Useful Lives [Member] | 
 
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| Notes Tables | 
 
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| Property, Plant and Equipment [Table Text Block] | 
  |   |  Years  |    |     | Equipment |  3  |  - |  7 |    |     | Leasehold improvements |  7 |  - |  10 or life of lease |    |     | Vehicles |    |  3 |    |    |      
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| Investments Classified by Contractual Maturity Date [Table Text Block] | 
  |   |    |  September 30,   2015 |    |  September 30,   2014 |     | Less than one year |    |  $ |  7,925,000 |    |    |  $ |  6,632,000 |    |     | 1-3 years |    |    |  8,290,000 |    |    |    |  8,302,000 |    |     | Total |    |  $ |  16,215,000 |    |    |  $ |  14,934,000 |    |      
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| Allowance for Credit Losses on Financing Receivables [Table Text Block] | 
  | Year Ended |    |  Balance at   Beginning of   Year |    |  Additions   Charged to   Costs and   Expenses |    |  Less   Write-offs |    |  Balance   at End   of Year |     | September 30, 2015 |    |  $ |  97,950 |    |    |  $ |  - |    |    |  $ |  (18,477 |  ) |    |  $ |  79,473 |    |     | September 30, 2014 |    |    |  97,950 |    |    |    |  - |    |    |    |  - |    |    |    |  97,950 |    |     | September 30, 2013 |    |    |  97,950 |    |    |    |  - |    |    |    |  - |    |    |    |  97,950 |    |      
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| Schedule of Inventory, Current [Table Text Block] | 
  |   |    |  September 30,  2015 |    |  September 30, 2014 |     |   |    |    |    |    |     | Raw materials |    |  $ |  4,811,993 |    |    |  $ |  3,729,160 |    |     | Work-in-process |    |    |  310,149 |    |    |    |  292,557 |    |     | Finished goods |    |    |  2,060,712 |    |    |    |  1,368,625 |    |     |   |    |  $ |  7,182,854 |    |    |  $ |  5,390,342 |    |      
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| Property, Plant and Equipment [Table Text Block] | 
  |   |    |  September 30,  2015 |    |  September 30,  2014 |     |   |    |    |    |    |    |    |    |    |     | Manufacturing Equipment |    |  $ |  4,102,868 |    |    |  $ |  3,057,665 |    |     | Office Equipment |    |    |  2,655,088 |    |    |    |  1,985,409 |    |     | Leasehold Improvements |    |    |  2,414,133 |    |    |    |  320,218 |    |     | Vehicles |    |    |  193,702 |    |    |    |  192,321 |    |     |   |    |    |  9,365,791 |    |    |    |  5,555,613 |    |     | Less accumulated depreciation |    |    |  3,676,118 |    |    |    |  3,093,363 |    |     |   |    |  $ |  5,689,673 |    |    |  $ |  2,462,250 |    |      
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| Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] | 
  | Year ended September 30, |    |  2015 |    |  2014 |    |  2013 |     | Net income |    |  $ |  4,682,008 |    |    |  $ |  5,432,851 |    |    |  $ |  4,733,844 |    |     | Weighted average common shares |    |    |  13,216,010 |    |    |    |  12,916,273 |    |    |    |  12,527,153 |    |     | Dilutive potential common shares |    |    |  371,522 |    |    |    |  685,321 |    |    |    |  551,786 |    |     | Weighted average dilutive common shares outstanding |    |    |  13,587,532 |    |    |    |  13,601,594 |    |    |    |  13,078,939 |    |     | Earnings per share: |    |    |    |    |    |    |    |    |    |    |    |    |     | Basic |    |  $ |  0.35 |    |    |  $ |  0.42 |    |    |  $ |  0.38 |    |     | Diluted |    |  $ |  0.34 |    |    |  $ |  0.40 |    |    |  $ |  0.36 |    |      
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