STOCKHOLDERS’ EQUITY - Narrative (Details) - USD ($)		3 Months Ended		9 Months Ended
	Nov. 06, 2018	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	May 13, 2024	Oct. 02, 2023	Sep. 30, 2023	Jan. 31, 2020	Mar. 07, 2018	Mar. 10, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to outstanding stock options and RSUs		$ 25,400,000		$ 25,400,000
Weighted average period for unrecognized compensation expense expected to be recognized (in years)				2 years 4 months 24 days
Purchase of common stock (in shares)		482,835		482,835				651,269
Recognized compensation expense		$ 3,585,000	$ 2,644,000	$ 10,901,000	$ 7,790,000
Options granted (in shares)				0	0
Amount authorized and approved under share repurchase program						$ 50,000,000.0
Amount of shares repurchased		$ 10,000,000.0		$ 10,000,000.0
Number of shares repurchased (in shares)		819,623		819,623
Average price of shares repurchased (in dollars per share)		$ 12.25		$ 12.25
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized compensation expense		$ 0	0	$ 0	$ 0
Unrecognized compensation expense related to options outstanding		$ 0		$ 0
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period for unrecognized compensation expense expected to be recognized (in years)				2 years 6 months
Awards outstanding (in shares)		2,385,346		2,385,346				2,188,296
Recognized compensation expense		$ 1,900,000	1,900,000	$ 6,800,000	5,400,000
Unrecognized compensation expense related to nonvested awards		$ 19,600,000		$ 19,600,000
Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period for unrecognized compensation expense expected to be recognized (in years)				1 year 9 months 18 days
Awards outstanding (in shares)		879,598		879,598				730,393
Recognized compensation expense		$ 600,000	600,000	$ 2,900,000	2,000,000.0
Unrecognized compensation expense related to nonvested awards		5,800,000		5,800,000
Performance options | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock reserved for future grants (in shares)	800,000
Recognized compensation expense		$ 1,000,000.0	$ 0	$ 1,000,000.0	0
Exercise price per share (in dollars per share)	$ 9.50
2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)							5,108,000		4,500,000
Number of common stock reserved for future grants (in shares)		4,435,200		4,435,200
2020 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (in shares)		2,218,360		2,218,360
2020 Plan | Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (in shares)		879,598		879,598
Prior Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)									107,903
Purchase of common stock (in shares)		265,656		265,656
Prior Plans | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (in shares)		0		0
ESPP common stock equivalents
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)										1,000,000
Number of common stock reserved for future grants (in shares)		270,876		270,876
Issuance of common stock under employee stock purchase plan (in shares)				729,124
Discount rate from market price, offering date				15.00%
Recognized compensation expense				$ 200,000	$ 200,000
Director Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)											1,500,000
Number of common stock reserved for future grants (in shares)		0		0
Director Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase of common stock (in shares)		166,986		166,986