INVESTMENTS - Summary of Investments by Type of Security (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Debt Securities, Available-for-sale [Line Items]
Cost	$ 59,431	$ 76,245
Gross Unrealized Gains	66	1
Gross Unrealized Losses	(124)	(242)
Fair Market Value	59,373	76,004
Short-Term | U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Cost	31,755	40,329
Gross Unrealized Gains	15	1
Gross Unrealized Losses	(83)	(76)
Fair Market Value	31,687	40,254
Short-Term | Commercial Paper
Debt Securities, Available-for-sale [Line Items]
Cost	18,622
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Market Value	18,622
Short-Term | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Cost	9,054	34,545
Gross Unrealized Gains	51	0
Gross Unrealized Losses	(41)	(99)
Fair Market Value	$ 9,064	34,446
Long-Term | U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Cost		1,371
Gross Unrealized Gains		0
Gross Unrealized Losses		(67)
Fair Market Value		$ 1,304