LICENSE AGREEMENTS (Details) € in Thousands, $ in Thousands		1 Months Ended				3 Months Ended		9 Months Ended
	Jul. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2016 USD ($)	Aug. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) option	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 EUR (€)	Sep. 30, 2019 USD ($)
Organization And Basis Of Presentation [Line Items]
Royalty rate		2.00%				2.00%		2.00%
Transaction price		$ 11,200				$ 11,200		$ 11,200
License revenue						11,236	$ 0	11,236		$ 0
Provision for income taxes						(1,132)	$ 0	(1,132)		$ 0
Qilu Pharmaceutical Co., Ltd.
Organization And Basis Of Presentation [Line Items]
Net proceeds associated with license agreement		10,000
Qilu Pharmaceutical Co., Ltd. | Licensing Agreements
Organization And Basis Of Presentation [Line Items]
Cash payment	$ 12,000	$ 12,000						200
Total milestone payments	$ 23,000
Royalty payment based on annual net sales	12.00%
License revenue						11,200
Provision for income taxes						$ 1,100		$ 1,100
University of Zurich
Organization And Basis Of Presentation [Line Items]
License agreement, royalty on net product sales, percentage								4.00%	4.00%
License agreement, rate requiring reduction in the amount of royalties owed								10.00%	10.00%
License agreement, royalty on net product sales, minimum								2.00%	2.00%
University of Zurich | Collaborative Arrangement, Revenue Based on Clinical Development Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone								$ 750
Micromet AG
Organization And Basis Of Presentation [Line Items]
License agreement, royalty on net product sales, percentage								3.50%	3.50%
Potential milestone payments | €									€ 3,600
License Agreement, royalty payment, reduction, conditions not met								1.50%	1.50%
License maintenance fees | €									€ 50
XOMA Ireland Limited
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone								$ 250
License agreement, royalty on net product sales, percentage								2.50%	2.50%
License agreement, rate requiring reduction in the amount of royalties owed								50.00%	50.00%
License agreement, royalty on net product sales, minimum								1.75%	1.75%
Roche
Organization And Basis Of Presentation [Line Items]
Up-front license fee				$ 7,500
Additional up-front fee				262,500
License agreement, option periods | option					2
License agreement, buyout amount under first option period					$ 135,000
License agreement, period to pay buyout option once exercised					30 days
License agreement, buyout amount under second option period					$ 265,000
License agreement, buyout amount under second option period, upon non-issuance of patent rights or licensed product					$ 220,000
License agreement, period for termination where sufficient development activities are not performed					12 months
Roche | First Indication
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				197,500
Roche | Collaborative Arrangement, Revenue Based on Development Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				72,500
Roche | Collaborative Arrangement, Revenue Based on Regulatory Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				50,000
Roche | Collaborative Arrangement, Revenue Based on Commercialization Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				$ 75,000
Roche | Second Indication
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone								$ 65,000
Roche | EBI-031 | Minimum
Organization And Basis Of Presentation [Line Items]
Royalty rate		7.50%				7.50%		7.50%
Roche | EBI-031 | Maximum
Organization And Basis Of Presentation [Line Items]
Royalty rate		15.00%				15.00%		15.00%
Roche | EBI-031 | Collaborative Arrangement, Revenue Based on Development Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone			$ 22,500
Roche | IL-6
Organization And Basis Of Presentation [Line Items]
Royalty rate		50.00%				50.00%		50.00%