Stock Purchase Warrants (Details 1) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Beginning Balance			$ 14,821
Change in fair value of warrant liability	$ 2,159	$ 3,513	7,249	$ 3,015
Ending Balance	$ 7,573		$ 7,573

Amount of expense (income) related to adjustment to fair value of warrant liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6939902&loc=d3e20148-110875

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration