Commitments and contingencies (Details) $ in Millions	3 Months Ended
Mar. 31, 2017 USD ($) Complaint
Commitments and contingencies [Abstract]
Amount of milestone payment payable	$ 6.0
Potential future milestone payments on each additional final marketing approval	$ 1.0
Number of competing derivative complaints \| Complaint	2
Litigation settlement	$ 0.7

Refers to number of competing derivative complaints against company.

No definition available.

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- Definition

The potential future milestone payments on each additional final marketing approval as of the balance sheet date.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

Amount of cash outflow reducing loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

+ Details

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- Definition

The fair value, as of the date of each statement of financial position presented, of other assets which are owned but transferred to serve as collateral for the payment of the related debt obligation, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

+ Details

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Data Type:	xbrli:monetaryItemType
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