Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 226,316	$ 286,470
Short term investments, Amortized cost	49,964	50,029
Gross unrealized gains	119	0
Gross unrealized losses	0	(86)
Short term investments, fair value	50,083	49,943
Equity securities, FV-NI, amortized cost	1,525	3,711
Equity securities, FV-NI, gross unrealized gains	0	0
Equity securities, FV-NI, unrealized loss	0	0
Fair value	1,525	3,711
Total cash, cash equivalents and investments, amortized cost	277,805	340,210
Total cash, cash equivalents and investments, fair value	277,924	340,124
Corporate bonds
Cash and Cash Equivalents [Line Items]
Short term investments, Amortized cost		14,918
Gross unrealized gains		0
Gross unrealized losses		(29)
Short term investments, fair value		14,889
U.S. government treasury bills
Cash and Cash Equivalents [Line Items]
Short term investments, Amortized cost	49,964	35,111
Gross unrealized gains	119	0
Gross unrealized losses	0	(57)
Short term investments, fair value	50,083	35,054
Cash
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	26,458	40,816
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 199,858	$ 245,654