Note 14 - Income Taxes (Details Textual) - USD ($) |
3 Months Ended | 12 Months Ended | |
|---|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
Dec. 31, 2017 |
|
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 35.00% | |
| Unrecognized Tax Benefits, Ending Balance | $ 0 | $ 0 | |
| Open Tax Year | 2014 2015 2016 2017 | ||
| Income Tax Expense (Benefit), Total | $ 0 | $ (1,454,172) | |
| Effective Income Tax Rate Reconciliation, Percent, Total | 0.00% | 33.70% | |
| Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | |||
| Operating Loss Carryforwards, Total | $ 131,800,000 | ||
| Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Research Tax Credit Carryforward [Member] | |||
| Tax Credit Carryforward, Amount | 9,700,000 | ||
| State and Local Jurisdiction [Member] | |||
| Operating Loss Carryforwards, Total | 20,400,000 | ||
| Other Noncurrent Assets [Member] | |||
| Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax | $ 1,200,000 | $ 1,200,000 | |
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carryforwards. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Tax year that remains open to examination under enacted tax laws, in CCYY format. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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