Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 5D
-Subparagraph (SX 210.12-13D(Column C))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=SL120429264-123010

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column C))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611197-123010

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LICENSE AND COLLABORATION AGREEMENTS - Biocartis (Details) - Biocartis N.V. - USD ($) $ in Millions	1 Months Ended
	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2018	Sep. 30, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Investment owned (in shares)			270,000
Investment owned, fair value		$ 1.5	$ 4.0
Licensing Agreements
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
One-time fee for a royalty-free, fully-paid, perpetual and assignable license to patents				$ 3.2
Early contract termination payment	$ 12.0