Note 2 - Significant Accounting Policies - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based compensation expense	$ 4,464	$ 12,581	$ 3,358
Research and Development Expense [Member]
Share-based compensation expense	2,020	3,558	1,635
General and Administrative Expense [Member]
Share-based compensation expense	2,162	7,537	1,723
Cost of Sales [Member]
Share-based compensation expense	$ 282	$ 1,486	$ 0

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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