| Note 8 - Lease Liability - Schedule of Right-of-use Asset Obtained in Exchange for Operating Lease Liability (Details) - USD ($) $ in Thousands | 6 Months Ended | ||
|---|---|---|---|
| Jun. 30, 2019 | Jan. 01, 2019 | Dec. 31, 2018 | |
| Operating Lease, Right-of-Use Asset | $ 1,573 | $ 1,570 | |
| Right-of-use assets obtained in exchange for new operatinglease liabilities in the period | $ 234 | 
| X | ||||||||||
| 
- Definition Amount of lessee's right to use underlying asset under operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Definition Amount of increase in right-of-use asset obtained in exchange for operating lease liability. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
 |