Product Warranties (Tables)

3 Months Ended

Dec. 31, 2017

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 month periods ended December 31, 2017 and 2016 were as follows:

	Three Months Ended December 31,
	2017			2016
Balance at beginning of period	$	431,000		$	650,000
Provision for warranties	83,000			114,000
Expenses incurred	(83,000		)	(114,000		)
Balance at end of period	$	431,000		$	650,000