Other Balance Sheet Information - Summary of Account Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 231,193	$ 195,587
Less allowance for expected credit losses	(5,736)	(7,216)
Accounts receivable, net	225,389	188,291
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowance for sales returns	$ (68)	$ (80)

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