Note 2 - Acquisitions - Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			9 Months Ended
	Mar. 31, 2021	Jan. 08, 2021	Sep. 30, 2021	Dec. 31, 2020
Goodwill, Ending Balance			$ 25,846	$ 23,966
rms Connectors, Inc. [Member]
Cash and cash equivalents		$ 0
Accounts receivable		1,283
Inventories		3,946
Other current assets		9
Property, plant and equipment		4,035
Intangible assets		0
Other assets		0
Total identifiable assets		9,273
Accounts payable		(62)
Accrued expenses		(209)
Total liabilities assumed		(271)
Net identifiable assets acquired		9,002
Goodwill, Ending Balance		0
Net assets acquired		9,002
Cash paid		9,002
Fair value of consideration transferred		$ 9,002
EOS Power Panama Inc. [Member]
Cash and cash equivalents	$ 3,903
Accounts receivable	1,805
Inventories	1,878
Other current assets	1,340
Property, plant and equipment	721
Intangible assets	2,000		2,000
Other assets	60
Total identifiable assets	11,707
Accounts payable	(2,148)
Accrued expenses	(506)
Total liabilities assumed	(2,654)
Net identifiable assets acquired	9,053
Goodwill, Ending Balance	2,659
Net assets acquired	11,712
Cash paid	11,712
Fair value of consideration transferred	$ 11,712
The 2021 Acquisitions [Member]
Cash and cash equivalents			3,903
Accounts receivable			3,088
Inventories			5,824
Other current assets			1,349
Property, plant and equipment			4,756
Intangible assets			2,000
Other assets			60
Total identifiable assets			20,980
Accounts payable			(2,210)
Accrued expenses			(715)
Total liabilities assumed			(2,925)
Net identifiable assets acquired			18,055
Goodwill, Ending Balance			2,659
Net assets acquired			20,714
Cash paid			20,714
Fair value of consideration transferred			$ 20,714