Note 2 - Significant Accounting Policies (Details Textual) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2018 |
Dec. 31, 2018 |
|
| Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | 10 years | |
| Subsequent Event [Member] | ||
| Operating Leases, Future Minimum Payments Due, Total | $ 2 |
| X | ||||||||||
- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|