Note 11 - Stock Based Compensation (Details) - Stock Option Activity - $ / shares	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Option Activity [Abstract]
Outstanding at January 1, 2013	1,744,755	861,905	725,529
Outstanding at January 1, 2013	$ 7.20	$ 12.30	$ 14.63
Outstanding balance	2,139,822	1,744,755	861,905
Outstanding balance	$ 5.64	$ 7.20	$ 12.30
Outstanding balance	7 years 6 months
Exercisable at December 31, 2015	1,315,201
Exercisable at December 31, 2015	$ 7.51
Exercisable at December 31, 2015	6 years 6 months
Granted	839,250	1,014,700	187,777
Granted	$ 2.35	$ 3.53	$ 4.39
Exercised			(12,429)
Exercised			$ 14.67
Canceled or expired	(444,183)	(131,850)	(38,972)
Canceled or expired	$ 5.56	$ 19.05	$ 16.79

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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Net number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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