Note 2 - Recently Issued and Adopted Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Mar. 31, 2019
Retained Earnings (Accumulated Deficit), Ending Balance	$ 522,639		$ 594,353	$ 610,302
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 900
Accounting Standards Update 2016-13 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		$ (500)