Nature of Operations and Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Doubtful Accounts (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Receivables [Abstract]
Balance, beginning of year	$ 459,000	$ 313,000
Provision for doubtful accounts	50,000	175,000
Provision for estimated returns and allowances	205,000	315,000
Uncollectible accounts written off	(5,000)	(71,000)
Returns and allowances issued	(267,000)	(273,000)
Balance, end of year	$ 442,000	$ 459,000