Note 1 - Significant Accounting Policies - Summary of Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Receivables	$ 3,602	$ 4,293
Billed Revenues [Member]
Receivables	2,587	2,714
Unbilled Revenues [Member]
Receivables	1,015	1,579
US Department of Health and Human Services [Member]
Receivables	1,987	1,525
US Department of Health and Human Services [Member] | Billed Revenues [Member]
Receivables	998
US Department of Health and Human Services [Member] | Unbilled Revenues [Member]
Receivables	989	1,525
Shionogi and Co. Ltd [Member]
Receivables	96	854
Shionogi and Co. Ltd [Member] | Billed Revenues [Member]
Receivables	96	854
Shionogi and Co. Ltd [Member] | Unbilled Revenues [Member]
Receivables
Green Cross Corporation [Member]
Receivables	542	904
Green Cross Corporation [Member] | Billed Revenues [Member]
Receivables	542	876
Green Cross Corporation [Member] | Unbilled Revenues [Member]
Receivables		28
Mundipharma International Holdings Limited [Member]
Receivables	49	44
Mundipharma International Holdings Limited [Member] | Billed Revenues [Member]
Receivables	49	44
Mundipharma International Holdings Limited [Member] | Unbilled Revenues [Member]
Receivables
Seqirus UK Limited [Member]
Receivables	928	966
Seqirus UK Limited [Member] | Billed Revenues [Member]
Receivables	902	940
Seqirus UK Limited [Member] | Unbilled Revenues [Member]
Receivables	$ 26	$ 26