Product Warranties (Tables)

6 Months Ended

Mar. 31, 2018

Product Warranties [Abstract]

Schedule of Product Warranty Liability [Table Text Block]

Changes in the Company's warranty liability (included in accrued expenses) for the three and six month periods ended March 31, 2018 and 2017 were as follows:

	Three Months Ended March 31,						Six Months Ended March 31,
	2018			2017			2018			2017
Balance at beginning of period	$	431,000		$	650,000		$	431,000		$	650,000
Provision for warranties	71,000			102,000			154,000			216,000
Expenses incurred	(70,000		)	(102,000		)	(153,000		)	(216,000		)
Balance at end of period	$	432,000		$	650,000		$	432,000		$	650,000