Commitments and Contingencies - Operating leases and purchase obligations (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Operating leases
Rent expense under operating leases	$ 141,000	$ 140,000	$ 113,000
Operating leases future minimum payments due	47,988	134,810
Purchase Obligations
Purchase obligations on open purchase orders	853,123	$ 1,082,928	$ 730,275
Product Liability
Product liability insurance	$ 50,000,000