Note 5 - Accounts Receivable - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts receivable, net	$ 6,190	$ 15,976
Royalties [Member]
Accounts receivable, net	4,789	4,304
Product Sales, License and Other [Member]
Accounts receivable, net	$ 1,401	$ 11,672

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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