QUARTERLY INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 37,656	$ 43,070	$ 46,123	$ 45,703	$ 39,626	$ 39,195	$ 33,510	$ 32,473	$ 172,552	$ 144,804	$ 119,797
Cost of revenue (exclusive of depreciation & amortization)	6,272	5,712	5,898	5,069	5,217	5,784	4,451	4,556
Operating expenses	34,671	35,566	31,539	32,261	30,610	32,518	26,379	23,089
Operating income (loss)	(3,287)	1,792	8,686	8,373	3,799	893	2,680	4,828	15,564	12,200	13,277
Interest expense	2,401	2,362	2,163	2,137	2,107	2,077	2,040	2,008	9,063	8,232	5,129
Other income, net	2,121	925	454	340	(365)	89	(225)	135	3,840	(366)	654
Income tax benefit (provision)	2,123	(783)	(1,808)	(1,846)	(976)	880	20	168	(2,314)	92	(824)
Net income	$ (1,444)	$ (428)	$ 5,169	$ 4,730	$ 351	$ (215)	$ 435	$ 3,123	$ 8,027	$ 3,694	$ 7,978
Net income (loss) per share:
Basic income (loss) per share (in dollars per share)	$ (0.03)	$ (0.01)	$ 0.11	$ 0.11	$ 0.01	$ 0	$ 0.01	$ 0.07	$ 0.18	$ 0.08	$ 0.18
Shares used in calculating net income (loss) per share—basic (in shares)	45,997	46,002	45,377	44,930	44,661	44,669	44,775	44,788	45,533	44,595	43,509
Diluted income (loss) per share (in dollars per share)	$ (0.03)	$ (0.01)	$ 0.11	$ 0.10	$ 0.01	$ 0	$ 0.01	$ 0.07	$ 0.17	$ 0.08	$ 0.18
Shares used in calculating net income (loss) per share - diluted (in shares)	47,050	46,473	45,780	45,634	45,311	45,224	46,097	46,155	46,461	45,780	45,083