Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Oct. 26, 2017
Document and Entity Information [Abstract]    
Entity Registrant Name OMNICELL, Inc  
Entity Central Index Key 0000926326  
Document Type 10-Q  
Document Period End Date Sep. 30, 2017  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   37,932,401
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3