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Note 6 - Stock Plans and Stock Based Compensation (Details) - Black-Scholes Valuation Model Assumptions (USD $) | 9 Months Ended
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Sep. 30, 2014 | Sep. 30, 2014 Director Stock Options [Member] | Sep. 30, 2013 Employee Stock Option [Member]
Note 6 - Stock Plans and Stock Based Compensation (Details) - Black-Scholes Valuation Model Assumptions [Line Items] |  |  |  |  |  |
Weighted-average fair value per share (in Dollars per share) | $ 2.88 |  | $ 2.73 |  | $ 1.96 |
Risk -free interest rate (1) | 1.91% | [1] | 2.63% | [1] | 2.92% | [1]
Expected volatility of stock (2) | 61.84% | [2] | 59.59% | [2] | 58.88% | [2]
Expected option life (3) (years) | 6 years | [3] | 10 years | [3] | 10 years | [3]
[1] | The risk-free interest rate is based on the U.S. Treasury yield in effect at the grant date over the expected term of the option.
[2] | The expected volatility is based on historical volatility from our traded Common Stock over the expected term of the option.
[3] | The expected option life is based on historical exercises and post-vesting data.

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- Definition Represents weighted average fair value per share assumption used in valuing an instrument. + References No definition available. + Details
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.D.2) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section D -Subsection 2 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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