Note 11 - Business Segment Information (Details) - Components of segment performance (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 17,279	$ 18,706	$ 38,298	$ 46,207
Segment contribution	(1,874)	(2,932)	(1,499)	(4,221)
Interest expense, net	(31)	(113)	(119)	(216)
Miscellaneous	2	(20)	(23)	32
Income taxes-current	(23)	(188)	(61)	(267)
Income taxes-deferred	(30)	17	(90)	5
Income (Loss) from discontinued operations	(120)	49	144	(22)
Noncontrolling interest	3	20	9	20
Net loss attributable to Ultralife	(2,073)	(3,167)	(1,639)	(4,669)
Total assets	91,135	92,991	91,135	92,991	97,718
Battery & Energy Products [Member]
Segment Reporting Information [Line Items]
Revenues	14,656	15,523	27,709	35,605
Segment contribution	3,490	3,763	6,590	7,706
Total assets	44,357	51,477	44,357	51,477
Communications Systems [Member]
Segment Reporting Information [Line Items]
Revenues	2,623	3,183	10,589	10,602
Segment contribution	1,032	704	4,311	3,354
Total assets	31,711	30,548	31,711	30,548
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Income (Loss) from discontinued operations	(120)	49	144	(22)
Total assets		2,759		2,759
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Segment contribution	(6,396)	(7,399)	(12,400)	(15,281)
Interest expense, net	(31)	(113)	(119)	(216)
Miscellaneous	2	(20)	(23)	32
Income taxes-current	(23)	(188)	(61)	(267)
Income taxes-deferred	(30)	17	(90)	5
Noncontrolling interest	3	20	9	20
Total assets	$ 15,067	$ 8,207	$ 15,067	$ 8,207