|
Note 13 - Stock-based Compensation Plan (Details) - Stock-based Compensation Expense (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Stock-based compensation expense | $ 2,091 | $ 1,174 | $ 676 |
| Research and Development Expense [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Stock-based compensation expense | 650 | 311 | 148 |
| General and Administrative Expense [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Stock-based compensation expense | $ 1,441 | $ 863 | $ 528 |