Note 11 - Stock Option and Equity Incentive Plans - Future Share-based Compensation Expense (Details) $ in Thousands	Dec. 31, 2016 USD ($)
2017	$ 337
2018	223
2019	110
2020	23
Total	693
Employee and Nonemployee Stock Option [Member]
2017	44
2018	16
2019
2020
Total	60
Common Stock [Member]
2017
2018
2019
2020
Total
Restricted Stock Units (RSUs) [Member]
2017	293
2018	207
2019	110
2020	23
Total	$ 633