Note 3 - Business Combination - Total Purchase Price for Aviragen (Details) - USD ($) $ in Thousands		12 Months Ended
Feb. 13, 2018	Dec. 31, 2018
Common stock	$ 31,789
Total	$ 31,789	$ 31,789

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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