Note 7 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 23, 2020
Operating Lease, Right-of-Use Asset, Amortization Expense	$ 325	$ 306
Lease Agreement, EMS Facility in Fremont, California [Member]
Lessee, Operating Lease, Renewal Term (Month)			5 years 30 days
Increase in Operating Lease Liabilities and Right-of-Use Assets, Non-cash	$ 1,176
Lease Agreement, Ambrell’s U.K [Member]
Lessee, Operating Lease, Term of Contract (Year)		15 years
Decrease In Operating Lease Liabilities and Right-of-Use Assets, Non-cash		$ 486