Note 2 - Recently Issued and Adopted Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019
Retained Earnings (Accumulated Deficit), Ending Balance	$ 520,025		$ 594,353	$ 579,920
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 1,800
Accounting Standards Update 2016-13 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		$ (500)