Note 5 - Stock-based Compensation (Details Textual) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2019 |
Mar. 31, 2018 |
|
| Share-based Payment Arrangement, Expense | $ 62,000 | $ 138,000 | |
| Share-based Payment Arrangement, Expense, Tax Benefit | 0 | $ 0 | |
| Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $ 166,000 | $ 166,000 | |
| Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition | 1 year 36 days | ||
| X | ||||||||||
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of tax benefit for recognition of expense of award under share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|