Note 6 - Third Amendment to Amended and Restated Certificate of Incorporation (Details Textual) - $ / shares	Jun. 30, 2018	Dec. 31, 2017	Jul. 07, 2017	May 31, 2015	Apr. 30, 2015
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01	$ 0.01		$ 0.01
Common Stock, Shares Authorized	192,000,000	192,000,000		192,000,000	96,000,000

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_CommonStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant