Note 3 - Goodwill and Acquired Intangible Assets - Components of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total, gross	$ 7,020
Total, accumulated amortization	954
Total, net	6,066	$ 1,669	$ 1,881
AZEDRA Product Rights [Member]
Total, gross	4,900
Total, accumulated amortization	291
Total, net	4,609
EXINI Technology [Member]
Total, gross	2,120
Total, accumulated amortization	663
Total, net	$ 1,457