Fair value of financial instruments - Rollforward of Level 3 liabilities (Details) $ in Thousands	3 Months Ended
Mar. 31, 2017 USD ($)
Rollforward of Level 3 liabilities
Change in fair value of contingent consideration	$ 7,356
ARIAD Pharmaceuticals
Rollforward of Level 3 liabilities
Royalties paid	4,100
Fair Value \| Level 3
Rollforward of Level 3 liabilities
Balance at beginning of period	301,000
Contingent consideration earned during the period but not yet paid	(4,356)
Change in fair value of contingent consideration	7,356
Balance at end of period	$ 304,000

Amount of decrease in the value of a contingent consideration liability attributable to consideration earned by the acquiree in a business combination.

No definition available.

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- References

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- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

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- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

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- Definition

Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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