ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment, long-term loan receivable	$ 3,500
Credit loss on finance receivable			$ 1,900
Reacquisition of equity component of convertible debt		$ (2,718)	(16,814)	$ (4,796)
Convertible Senior Notes, 5.0% | Convertible notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reacquisition of equity component of convertible debt	$ 19,500	$ (2,700)	$ (16,800)