Fair Value Measurements - Summary of Financial Assets that are Measured at Fair Value and Indicates the Fair Value Hierarchy of the Valuation Inputs (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, cost		$ 9,883
Commercial Paper | Short-term investment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, cost	$ 13,489
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, cost		$ 1,780
Corporate Bonds | Short-term investment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, cost	3,608
Corporate Bonds | Long-term investment
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, cost	$ 933