Note 12 - Business Segment Information - Segment Activity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Revenues	[1]	$ 25,814	$ 18,882
Segment contribution		1,485	548
Other income (expense)		(92)	(58)
Tax provision		(319)	(41)
Non-controlling interest		(15)	(24)
Net income attributable to Ultralife		1,059	425
Battery & Energy Products Segment [Member]
Revenues	[1]	20,761	15,998
Segment contribution		5,316	4,410
Communications Systems Segment [Member]
Revenues	[1]	5,053	2,884
Segment contribution		2,018	674
Corporate Segment [Member]
Revenues
Segment contribution		(5,849)	(4,536)
Other income (expense)		(92)	(58)
Tax provision		(319)	(41)
Non-controlling interest		$ (15)	$ (24)

[1] Sales classified to U.S. include shipments to U.S.-based prime contractors which in some cases may serve non-U.S. projects