Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data	Oct. 02, 2011	Dec. 31, 2010
Current assets:
Allowance for doubtful accounts	$ 525	$ 490
Ultralife equity:
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	18,695,571	18,639,683
Treasury securities, common shares	1,372,757	1,371,900