Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019 USD ($)
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total			$ 0.3
Operating Lease, Right-of-Use Asset			$ 0.3
Customer Concentration Risk [Member] \| Revenue Benchmark [Member]
Number of Major Customers	3	3
Concentration Risk, Percentage	55.00%	47.00%
Customer Concentration Risk [Member] \| Accounts Receivable [Member]
Number of Major Customers	3
Concentration Risk, Percentage	28.00%

Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

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- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

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