Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	$ 23,836	$ 20,195
Debt Securities, Trading, and Equity Securities, FV-NI	31,884	25,513
Cash and Cash Equivalents
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	195,354	157,394
Debt Securities, Trading, and Equity Securities, FV-NI	195,354	157,394
Cash and Cash Equivalents | Cash
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	195,160	122,119
Debt Securities, Trading, and Equity Securities, FV-NI	195,160	122,119
Cash and Cash Equivalents | Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	194	35,275
Debt Securities, Trading, and Equity Securities, FV-NI	$ 194	$ 35,275