INVESTMENTS - Fair Value of Investments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Sep. 30, 2023
Assets:
Short-term investments:	$ 42,987	$ 74,700
Long-term investments:	6,337	1,304
Total assets at fair value	49,324	76,004
Liabilities:
Acquisition-related contingent consideration	0	7,976
Total liabilities at fair value		7,976
U.S. Treasury
Assets:
Short-term investments:	19,152	40,254
Long-term investments:	4,379	1,304
Commercial paper
Assets:
Short-term investments:	16,243
Corporate debt securities
Assets:
Short-term investments:	7,592	34,446
Long-term investments:	1,958
Quoted Prices in Active Markets (Level 1)
Assets:
Short-term investments:	19,152	40,254
Long-term investments:	4,379	1,304
Total assets at fair value	23,531	41,558
Liabilities:
Acquisition-related contingent consideration		0
Total liabilities at fair value		0
Quoted Prices in Active Markets (Level 1) | U.S. Treasury
Assets:
Short-term investments:	19,152	40,254
Long-term investments:	4,379	1,304
Quoted Prices in Active Markets (Level 1) | Commercial paper
Assets:
Short-term investments:	0
Quoted Prices in Active Markets (Level 1) | Corporate debt securities
Assets:
Short-term investments:	0	0
Long-term investments:	0
Significant Other Observable Inputs (Level 2)
Assets:
Short-term investments:	23,835	34,446
Long-term investments:	1,958	0
Total assets at fair value	25,793	34,446
Liabilities:
Acquisition-related contingent consideration		7,976
Total liabilities at fair value		7,976
Significant Other Observable Inputs (Level 2) | U.S. Treasury
Assets:
Short-term investments:	0	0
Long-term investments:	0	0
Significant Other Observable Inputs (Level 2) | Commercial paper
Assets:
Short-term investments:	16,243
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Assets:
Short-term investments:	7,592	34,446
Long-term investments:	1,958
Significant Unobservable Inputs (Level 3)
Assets:
Short-term investments:	0	0
Long-term investments:	0	0
Total assets at fair value	0	0
Liabilities:
Acquisition-related contingent consideration
Total liabilities at fair value		0
Significant Unobservable Inputs (Level 3) | U.S. Treasury
Assets:
Short-term investments:	0	0
Long-term investments:	0	0
Significant Unobservable Inputs (Level 3) | Commercial paper
Assets:
Short-term investments:	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Assets:
Short-term investments:	0	$ 0
Long-term investments:	$ 0