Note 9 - Cash, Cash Equivalents, Investments and Restricted Cash - Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 260,604	$ 189,265
Restricted cash included in other long-term assets	122	124
Total cash, cash equivalents and restricted cash reported on the Condensed Consolidated Statements of Cash Flows	$ 260,726	$ 189,389	$ 218,487	$ 335,071