Note 3 - Revenue (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017
Contract with Customer, Liability, Total	$ 67
Inventory Recall Expense		$ 1,100	$ 900
DePuy Mitek Inc [Member]
Revenues From Agreements as Percent of Total Revenue	72.00%	76.00%