Note 8 - Leases (Details Textual) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 08, 2019 ft²	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 22, 2020 ft²	Jan. 23, 2020	Mar. 31, 2019
Operating Lease, Right-of-Use Asset, Amortization Expense		$ 324	$ 351	$ 977	$ 952
Mansfield, Massachusetts [Member]
Lessee, Operating Lease, Renewal Term (Month)	3 years 120 days
Increase in Operating Lease Liabilities and Right-of-Use Assets, Non-cash					1,811
Operating Lease, Increase in Area (Square Foot) | ft²	6,100
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, EMS Facility in Mt. Laurel, New Jersey [Member]
Lessee, Operating Lease, Renewal Term (Month)						10 years
Increase in Operating Lease Liabilities and Right-of-Use Assets, Non-cash				$ 2,051
Area of Real Estate Property (Square Foot) | ft²						33,650
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
Lease Agreement, Ambrell’s Netherlands Facility [Member]
Decrease In Operating Lease Liabilities and Right-of-Use Assets, Non-cash			$ 48		$ 48