Note 2 - Acquisitions - Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		13 Months Ended
	Dec. 03, 2019	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Goodwill, Ending Balance		$ 23,966	$ 21,993	$ 10,800
Majority Products Business of CUI Power [Member]
Total identifiable assets	$ 9,764	25,176
Total identifiable assets		15,412
Total liabilities assumed	(6,855)	(6,855)
Net identifiable assets acquired	2,909	18,321
Net identifiable assets acquired		15,412
Goodwill, Ending Balance	29,091	10,875
Goodwill		(18,216)
Net assets acquired	32,000	29,196
Net assets acquired		(2,804)
Payments to Acquire Businesses, Gross	32,000	29,196
Cash paid		(2,804)
Business Combination, Consideration Transferred, Total	$ 32,000	29,196
Fair value of consideration transferred		$ (2,804)