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Note 1 - Significant Accounting Policies (Details Textual) shares in Thousands, $ in Thousands | 3 Months Ended | 6 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2018 USD ($) shares | Jun. 30, 2017 USD ($) shares | Jun. 30, 2018 USD ($) shares | Jun. 30, 2017 USD ($) shares | Jul. 10, 2018 USD ($) | Dec. 31, 2017 USD ($) | Sep. 23, 2016 USD ($) | Dec. 31, 2015 USD ($) | Mar. 09, 2011 USD ($)
Long-term Line of Credit, Total | $ 13,469 |  | $ 13,469 |  |  | $ 16,750 |  |  |
Restricted Cash and Cash Equivalents, Current, Total | 7,625 |  | 7,625 |  |  | 3,286 |  |  |
Loss on Sale of Investments |  |  | 0 |  |  |  |  |  |
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax |  |  | 0 | $ 1 |  |  |  |  |
Interest Expense, Debt, Total | 2,195 | $ 2,094 | 4,416 | 4,194 |  |  |  |  |
Amortization of Debt Issuance Costs | 223 | 220 | 455 | 439 |  |  |  |  |
Interest Expense, Total | 2,195 | $ 2,094 | 4,416 | $ 4,194 |  |  |  |  |
Lease Financing Obligation, Net of Current | $ 2,711 |  | $ 2,711 |  |  | 2,751 |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares | 1,939 | 2,208 | 1,854 | 2,475 |  |  |  |  |
RAPIVAB [Member] | Customer Concentration Risk [Member] | Sales Revenue, Product Line [Member] |  |  |  |  |  |  |  |  |
Number of Major Customers |  |  | 3 |  |  |  |  |  |
RAPIVAB [Member] | Customer Concentration Risk [Member] | Sales Revenue, Product Line [Member] | Three Customers [Member] |  |  |  |  |  |  |  |  |
Concentration Risk, Percentage |  |  | 90.00% |  |  |  |  |  |
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |  |  |  |  |  |
Derivative, Loss on Derivative |  |  | $ 1,186 | $ 1,943 |  |  |  |  |
Derivative, Gain on Derivative |  |  | 889 | 921 |  |  |  |  |
Currency Hedge Agreement [Member] |  |  |  |  |  |  |  |  |
Collateral Already Posted, Aggregate Fair Value | $ 0 |  | 0 |  |  | 0 |  |  |
Birmingham Research Facility [Member] |  |  |  |  |  |  |  |  |
Interest Expense, Total | 84 | $ 55 | 167 | $ 135 |  |  |  |  |
Lease Financing Obligation, Net of Current | 2,703 |  | 2,703 |  |  | $ 2,703 |  |  |
Capital Leases, Future Minimum Payments Due, Total | 4,114 |  | $ 4,114 |  |  |  |  |  |
Computer Equipment [Member] |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 3 years |  |  |  |  |  |
Laboratory Equipment, Office Equipment and Software [Member] |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 5 years |  |  |  |  |  |
Furniture and Fixtures [Member] |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 7 years |  |  |  |  |  |
Leasehold Improvements [Member] | Birmingham Research Facility [Member] |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 20 years 182 days |  |  |  |  |  |
Property, Plant and Equipment, Gross, Ending Balance |  |  |  |  |  |  |  | $ 1,589 |
Maximum [Member] |  |  |  |  |  |  |  |  |
Maturity Period of High Quality Marketable Securities |  |  | 3 years |  |  |  |  |  |
Average Maturity Period of High Quality Marketable Securities |  |  | 1 year 180 days |  |  |  |  |  |
Maturity Period of Short Term Investment |  |  | 1 year |  |  |  |  |  |
Average Maturity for Portfolio Investments |  |  | 1 year 180 days |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |
Maturity Period of Short Term Investment |  |  | 90 days |  |  |  |  |  |
Long-term Investment Maturity, Minimum |  |  | 1 year |  |  |  |  |  |
Royalty Receivable [Member] |  |  |  |  |  |  |  |  |
Restricted Cash and Cash Equivalents, Current, Total | 6,213 |  | $ 6,213 |  |  |  |  |  |
Collateral for Credit [Member] |  |  |  |  |  |  |  |  |
Restricted Cash and Cash Equivalents, Current, Total | 1,412 |  | 1,412 |  |  |  |  |  |
Senior Credit Facility [Member] | MidCap Financial Services, LLC [Member] |  |  |  |  |  |  |  |  |
Long-term Line of Credit, Total | $ 19,550 |  | $ 19,550 |  |  |  | $ 23,000 |  |
JPR Royalty Sub LLC [Member] |  |  |  |  |  |  |  |  |
Revenue Recognition Royalty and Milestone Revenue Recognized |  |  |  |  |  |  |  |  | $ 30,000
Subsequent Event [Member] |  |  |  |  |  |  |  |  |
Business Combination, Agreement Terminated, Expected Transaction-related Expenses |  |  |  |  | $ 6,000 |  |  |  |

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