v3.8.0.1
Document And Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Feb. 01, 2018
Jun. 30, 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)   15,653,649  
Entity Public Float     $ 69,474,629
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
Amendment Flag false