Organization and Summary of Significant Accounting Policies - Summary of Customer Allowances for Trade Promotions and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Accounting Policies [Abstract]
Trade promotions	$ 1,556	$ 2,153
Allowance for doubtful accounts	14	183
Trade promotions and allowance for doubtful accounts	$ 1,570	$ 2,336