Note 6 - Operating Lease Right-of-use Asset, Net - Impact of New Lease Standard (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Straight-line rent expense recognized for operating lease	$ 150,000	$ 153,000
Variable rent expense recognized for operating lease	75,000
Total lease cost	$ 225,000
Weighted average remaining lease term (in years) (Year)	2 years 273 days
Weighted average discount rate	12.05%

Amount of operating lease expense from variable lease payments.

No definition available.

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- Definition

Amount of lease cost recognized by lessee for lease contract.

+ References

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-Publisher FASB
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- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

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-Publisher FASB
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- Definition

Weighted average discount rate for operating lease calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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