Note 10 - Share Capital (Details Textual)	6 Months Ended
Jun. 30, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	242,729
Stock Issued During Period, Shares, Restricted Stock Award, Gross	53,591

Number of share options (or share units) exercised during the current period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 2
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 505
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration