Note 9 - Cost-reduction Actions (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018
Restructuring Reserve, Ending Balance		$ 102	$ 87	$ 89	$ 102
Facility Closing [Member] | Johor, Malaysia [Member] | Cost of Sales [Member]
Severance Costs		$ 67	112
Facility Closing [Member] | Johor, Malaysia [Member] | Selling, General and Administrative Expenses [Member]
Severance Costs			$ 29
Facility Closing [Member] | SPAIN | Cost of Sales [Member]
Severance Costs	$ 635
Facility Closing [Member] | SPAIN | Selling, General and Administrative Expenses [Member]
Severance Costs	$ 67