Nature of Operations and Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Doubtful Accounts (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Receivables [Abstract]
Balance, beginning of year	$ 313,000	$ 207,000
Provision for doubtful accounts	175,000	210,000	[1]
Provision for estimated returns and allowances	315,000	265,000
Uncollectible accounts writtenoff	(71,000)	(76,000)
Returns and allowances issued	(273,000)	(293,000)
Balance, end of year	$ 459,000	$ 313,000

[1] The amounts for the year ended September 30, 2018 have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 2 to the Consolidated Financial Statements.