Note 9 - Cash Equivalents, Investments and Restricted Cash - Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 218,368	$ 334,944
Restricted cash included in other long-term assets	119	127
Total cash, cash equivalents and restricted cash reported on the Condensed Consolidated Statements of Cash Flows	$ 218,487	$ 335,071	$ 154,996	$ 173,076