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Summary of Significant Accounting Policies - Fair Value (Details) - USD ($)
3 Months Ended
Dec. 31, 2019
Sep. 30, 2019
Warranty    
Length of warranty period 24 months  
Self-Insurance Reserves    
Estimated liability for medical claims incurred but not reported $ 51,000 $ 55,700
Excess of funded premiums over estimated claims incurred but not reported 190,100 123,100
Fair value on a recurring basis | Quoted Price in Active Markets for Identical Assets (Level 1) | Money market funds    
Assets    
Cash and cash equivalents $ 21,517,492 $ 21,450,242