Note 11 - Segment Information - Assets by Geographic Area (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Long-lived assets	$ 79,947	$ 75,057
Total assets	108,717	127,316
UNITED STATES
Long-lived assets	77,520	72,562
Total assets	91,442	110,785
CANADA
Long-lived assets	2,427	2,495
Total assets	$ 17,275	$ 16,531