Note 6 - Fair Value of Financial Instruments - Level 3 Rollforward (Details) - Fair Value, Inputs, Level 3 [Member] - Derivative Financial Instruments, Liabilities [Member] $ in Thousands	6 Months Ended
Jun. 30, 2016 USD ($)
Balance	$ 223
Change in fair value of common stock warrant liability	(223)
Balance

Amount of gain (loss) recognized on the income statement for 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.

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)(1)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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