v2.4.0.8
Document and Entity Information
3 Months Ended
Apr. 03, 2015
May 13, 2015
Document and Entity Information    
Entity Registrant Name Willdan Group, Inc.  
Entity Central Index Key 0001370450  
Document Type 10-Q  
Document Period End Date Apr. 03, 2015  
Amendment Flag false  
Current Fiscal Year End Date --01-02  
Entity Current Reporting Status Yes  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   7,819,582
Document Fiscal Year Focus 2015  
Document Fiscal Period Focus Q1