v3.8.0.1
Document And Entity Information - shares
9 Months Ended
Oct. 01, 2017
Oct. 31, 2017
Document Information [Line Items]    
Entity Registrant Name Ultralife Corp  
Entity Central Index Key 0000875657  
Trading Symbol ulbi  
Current Fiscal Year End Date --12-31  
Entity Filer Category Smaller Reporting Company  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Well-known Seasoned Issuer No  
Entity Common Stock, Shares Outstanding (in shares)   15,627,513
Document Type 10-Q  
Document Period End Date Oct. 01, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3  
Amendment Flag false