Note 1 - Significant Accounting Policies - Summary of Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables	$ 3,598	$ 4,293
Billed Revenues [Member]
Receivables	1,927	2,714
Unbilled Revenues [Member]
Receivables	1,671	1,579
US Department of Health and Human Services [Member]
Receivables	1,769	1,525
US Department of Health and Human Services [Member] | Billed Revenues [Member]
Receivables	477
US Department of Health and Human Services [Member] | Unbilled Revenues [Member]
Receivables	1,292	1,525
Shionogi and Co. Ltd [Member]
Receivables	160	854
Shionogi and Co. Ltd [Member] | Billed Revenues [Member]
Receivables	160	854
Shionogi and Co. Ltd [Member] | Unbilled Revenues [Member]
Receivables
Green Cross Corporation [Member]
Receivables	330	904
Green Cross Corporation [Member] | Billed Revenues [Member]
Receivables	303	876
Green Cross Corporation [Member] | Unbilled Revenues [Member]
Receivables	27	28
Mundipharma International Holdings Limited [Member]
Receivables	40	44
Mundipharma International Holdings Limited [Member] | Billed Revenues [Member]
Receivables	40	44
Mundipharma International Holdings Limited [Member] | Unbilled Revenues [Member]
Receivables
Seqirus UK Limited [Member]
Receivables	1,299	966
Seqirus UK Limited [Member] | Billed Revenues [Member]
Receivables	947	940
Seqirus UK Limited [Member] | Unbilled Revenues [Member]
Receivables	$ 352	$ 26