Note 8 - Leases - Lease Modifications (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 01, 2020	Dec. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Lease Agreement, EMS Facility in Fremont, California [Member]
Non-cash increases in operating lease liabilites and ROU assets				$ 1,176		$ 1,176
Lease Agreement, Ambrell’s U.K [Member]
Modification to lease for Ambrell’s U.K. facility					$ (486)		$ (486)
Lease Agreement, EMS Facility in Mt. Laurel, New Jersey [Member]
Non-cash increases in operating lease liabilites and ROU assets						2,051
Lease for Facility in Mansfield, Massachusetts [Member]
Non-cash increases in operating lease liabilites and ROU assets							1,811
Lease Agreement, Ambrell’s Netherlands Facility [Member]
Non-cash increases in operating lease liabilites and ROU assets	$ 133					133
Modification to lease for Ambrell’s U.K. facility			$ (48)				$ (48)
Automobile Leases [Member]
Non-cash increases in operating lease liabilites and ROU assets		$ 91				$ 91