Nature of Operations and Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Doubtful Accounts (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Receivables [Abstract]
Balance, beginning of year	$ 442,000	$ 459,000
Provision for doubtful accounts	50,000	50,000
Provision for estimated returns and allowances	175,000	205,000
Uncollectible accounts written off	(60,000)	(5,000)
Returns and allowances issued	(286,000)	(267,000)
Balance, end of year	$ 321,000	$ 442,000