Note 17 - Loss Per Common Share (Details Textual) - $ / shares
|
12 Months Ended |
|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Jul. 15, 2015 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price |
$ 0.15
|
$ 0.21
|
$ 0.21
|
|
| Minimum [Member] |
|
|
|
|
| Class of Warrant or Right, Exercise Price of Warrants or Rights |
|
|
|
$ 0.48
|
| Maximum [Member] |
|
|
|
|
| Class of Warrant or Right, Exercise Price of Warrants or Rights |
|
|
|
$ 0.49
|
| Employee Stock Option [Member] |
|
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount |
47,582,402
|
41,910,734
|
27,540,899
|
|
| Employee Stock Option [Member] | Minimum [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price |
$ 0.07
|
$ 0.08
|
$ 0.08
|
|
| Employee Stock Option [Member] | Maximum [Member] |
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price |
$ 0.77
|
$ 1.44
|
$ 2.33
|
|
| Warrant [Member] |
|
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount |
41,924,653
|
36,509,931
|
66,057,792
|
|
| Warrant [Member] | Minimum [Member] |
|
|
|
|
| Class of Warrant or Right, Exercise Price of Warrants or Rights |
$ 0.07
|
$ 0.17
|
$ 0.18
|
|
| Warrant [Member] | Maximum [Member] |
|
|
|
|
| Class of Warrant or Right, Exercise Price of Warrants or Rights |
$ 0.17
|
$ 0.19
|
$ 0.49
|
|