Note 13 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Warrants and Rights Outstanding	$ 19	$ 22
Series F Warrants and Series K Warrants [Member] \| Monte-Carlo model and Black-Scholes Models [Member] \| Fair Value, Inputs, Level 3 [Member]
Warrants and Rights Outstanding	20	20
Convertible 2020 Notes [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net, Total	$ 0	$ 400

Net fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as assets, net of those classified as liabilities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

Name:	us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant