Fair Value of Financial Instruments - Level 3 Roll Forward (Details) $ in Thousands	6 Months Ended
Jun. 30, 2018 USD ($)
Series D preferred stock warrants
Fair values of preferred stock warrant liabilities and common stock warrant liability
Beginning Balance	$ 992
Change in fair value	1,378
Exercise of common stock warrants / Conversion to common stock warrants	(2,370)
Ending Balance	0
Common stock warrants
Fair values of preferred stock warrant liabilities and common stock warrant liability
Beginning Balance	1,774
Change in fair value	7,460
Exercise of common stock warrants / Conversion to common stock warrants	(9,234)
Ending Balance	$ 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Amount of settlements 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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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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