Note 2 - Summary of Significant Accounting Policies - Fair Value Measurements Recurring Basis (Details) - USD ($) $ in Thousands |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Warrant liability | $ 140 | $ 42 |
| Fair Value, Recurring [Member] | ||
| Total financial liabilities | 140 | 42 |
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | ||
| Total financial liabilities | ||
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | ||
| Total financial liabilities | ||
| Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | ||
| Total financial liabilities | 140 | 42 |
| Warrant [Member] | Fair Value, Recurring [Member] | ||
| Warrant liability | 140 | 42 |
| Warrant [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | ||
| Warrant liability | ||
| Warrant [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | ||
| Warrant liability | ||
| Warrant [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | ||
| Warrant liability | $ 140 | $ 42 |