Note 10 - Cash, Cash Equivalents, Investments and Restricted Cash - Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 181,769	$ 172,704
Restricted cash included in other long-term assets	113	114
Total cash, cash equivalents and restricted cash reported in the Condensed Consolidated Statements of Cash Flows	$ 181,882	$ 172,818	$ 76,134	$ 82,874