Fair value measurements - Level 3 (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Dec. 31, 2016
Warrant Liability
Changes in level 3
Beginning Balance	$ 1,898
Change in estimated fair value	62
Ending Balance	1,960
Non-recurring
Changes in level 3
Fair value measurements	$ 0	$ 0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of increase (decrease) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

+ Details

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- Definition

Fair value of asset after deduction of liability.

+ References

No definition available.

+ Details

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- Details

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- Details

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