LICENSE AGREEMENTS (Details) € in Thousands			1 Months Ended			3 Months Ended							9 Months Ended			12 Months Ended
	Aug. 05, 2021 USD ($)	Jul. 30, 2020 USD ($)	Sep. 30, 2016 USD ($)	Aug. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) option	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2021 EUR (€)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Organization And Basis Of Presentation [Line Items]
Royalty rate						2.00%							2.00%	2.00%
License and related revenue						$ 0						$ 11,236,000	$ 6,544,000		$ 11,236,000
Benefit (provision) from income taxes						(8,561,000)						1,132,000	$ (8,273,000)		1,132,000
Transaction price										$ 11,200,000		11,200,000			$ 11,200,000	$ 11,200,000
Qilu Pharmaceutical Co., Ltd. | Licensing Agreements
Organization And Basis Of Presentation [Line Items]
Potential milestone payments								$ 23,000,000
Total milestone payments		$ 23,000,000
Royalty payment based on annual net sales		12.00%
License and related revenue							$ 900,000	2,800,000				$ 11,200,000
Milestone payment								3,000,000
Outstanding payments								2,800,000
Cash payment		$ 12,000,000														12,000,000
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%
Expenses related to achievement of development milestone						$ 500,000				300,000
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													$ 500,000
Micromet AG
Organization And Basis Of Presentation [Line Items]
License agreement, royalty on net product sales, percentage													3.50%	3.50%
Expenses related to achievement of development milestone								600,000	€ 500	900,000	€ 700
Potential milestone payments													$ 2,800,000	€ 2,400
License Agreement, royalty payment, reduction, conditions not met													1.50%	1.50%
License maintenance fees													$ 57,965	€ 50
XOMA Ireland Limited
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone													$ 250,000
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				$ 7,500,000
Additional up-front fee				262,500,000
License agreement, option periods | option					2
License agreement, buyout amount under first option period					$ 135,000,000
License agreement, period to pay buyout option once exercised					30 days
License agreement, buyout amount under second option period					$ 265,000,000
License agreement, buyout amount under second option period, upon non-issuance of patent rights or licensed product					$ 220,000,000
Roche | First Indication
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				197,500,000
Roche | Collaborative Arrangement, Revenue Based on Development Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				72,500,000
Roche | Collaborative Arrangement, Revenue Based on Regulatory Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				50,000,000
Roche | Collaborative Arrangement, Revenue Based on Commercialization Milestone
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				75,000,000
Roche | Collaborative Arrangement, Revenue Based on Development Milestone, Phase II
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone				$ 20,000,000
Roche | Second Indication
Organization And Basis Of Presentation [Line Items]
License agreement, amount payable upon achievement of specified milestone													$ 65,000,000
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			$ 22,500,000
Roche | IL-6
Organization And Basis Of Presentation [Line Items]
Royalty rate						50.00%							50.00%	50.00%
MENA License Agreement | Licensing Agreements
Organization And Basis Of Presentation [Line Items]
License and related revenue								1,500,000
Cash payment								$ 3,000,000
Transaction price										$ 1,500,000						$ 1,500,000
Percentage of upfront payment										0.50						0.50
EIP Agreement
Organization And Basis Of Presentation [Line Items]
Potential milestone payments	$ 2,000,000
Transaction price	$ 1,500,000
EIP Agreement | Turkey
Organization And Basis Of Presentation [Line Items]
Percentage of upfront payment	0.30