Note 1 - Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Revenue	$ 6,248	$ 4,281
AZEDRA Product Sales [Member
Revenue	1,359
Royalty [Member]
Revenue	4,789	4,161
License and Other [Member]
Revenue	$ 100	$ 120

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details