FUTURE ACQUISITION RIGHT AND JOINT DEVELOPMENT AGREEMENT (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2019	Jan. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jun. 30, 2016
Variable Interest Entity [Line Items]
Business combination-related contingent consideration			$ 71,300		$ 71,300		$ 70,900	$ 25,000
Investment			15,000		15,000
Impairment of long-term investment	$ 15,000		$ 0	$ 15,000	$ 0	$ 15,000
Censa Pharmaceuticals Inc.
Variable Interest Entity [Line Items]
Payments for the option to acquire business		$ 10,000
Business combination-related contingent consideration		19,900
Censa Pharmaceuticals, Inc, Equity Holders
Variable Interest Entity [Line Items]
Additional required payments for the option to acquire business, successful development milestones		$ 5,000