Other Balance Sheet Information - Summary of Account Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 189,059	$ 169,317
Less allowance for doubtful accounts	(5,805)	(3,644)
Accounts receivable, net	183,167	165,602
Allowance for Sales Returns
Valuation and Qualifying Accounts Disclosure [Line Items]
Less allowance for sales returns	$ (87)	$ (71)