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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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Average maturity for portfolio investments during the period.

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