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Note 6 - Income Taxes (Details) - Significant Components of Deferred Tax Assets and Liabilities (USD $)
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Dec. 31, 2014
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Dec. 31, 2013
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|---|---|---|
| Significant Components of Deferred Tax Assets and Liabilities [Abstract] | ||
| U.S. federal and state net operating loss carryforwards | $ 59,689,264 | $ 41,359,722 |
| Foreign net operating loss carryforwards | 1,743,603 | 1,827,221 |
| Contribution carryforwards | 4,245 | 3,055 |
| Research and development credits | 5,253,055 | 4,061,844 |
| Investment tax credits | 35,108 | 38,175 |
| Stock-based compensation | 462,796 | 22,282 |
| Patents and other intangibles | 611 | 2,967 |
| Other accruals | 125,614 | 97,157 |
| Deferred revenue | 372,040 | |
| Property and equipment | 510,466 | 532,316 |
| Total deferred tax assets | 68,196,802 | 47,944,739 |
| Valuation allowance for deferred assets | (68,196,802) | (47,944,739) |
| Net deferred tax assets | $ 0 | $ 0 |