COLLABORATION AND LICENSE AGREEMENTS - Change in Deferred Revenue (Details) $ in Thousands	12 Months Ended
Dec. 31, 2020 USD ($)
Change in Contract with Customer, Liability, Rollforward [Roll Forward]
Beginning—January 1, 2020	$ 6,143
Amounts invoiced	3,508
Revenue recognized	(9,384)
Ending—December 31, 2020	267
Product revenue
Change in Contract with Customer, Liability, Rollforward [Roll Forward]
Beginning—January 1, 2020	13
Amounts invoiced	403
Revenue recognized	(149)
Ending—December 31, 2020	267
Collaboration and license revenue \| Novartis
Change in Contract with Customer, Liability, Rollforward [Roll Forward]
Beginning—January 1, 2020	6,130
Amounts invoiced	3,105
Revenue recognized	(9,235)
Ending—December 31, 2020	$ 0

Change in Contract with Customer, Liability, Rollforward

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- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130532-203044

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- Definition

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130551-203045

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- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045

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