Note 6 - Derivative Obligations - Fair Value Hierarchy (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Derivative obligations	$ 338,000	$ 597,000
Fair Value, Inputs, Level 1 [Member]
Derivative obligations
Fair Value, Inputs, Level 2 [Member]
Derivative obligations
Fair Value, Inputs, Level 3 [Member]
Derivative obligations	$ 338,000	$ 597,000

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Name:	us-gaap_DerivativeLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant