Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents	$ 172,704	$ 82,759
Restricted cash included in other long-term assets	114	115
Total cash, cash equivalents and restricted cash reported in the Consolidated Statements of Cash Flows	$ 172,818	$ 82,874	$ 112,813	$ 90,973