Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 01, 2019
Document And Entity Information [Abstract]    
Entity Registrant Name Albireo Pharma, Inc.  
Entity Central Index Key 0001322505  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Document Type 10-Q  
Document Period End Date Mar. 31, 2019  
Entity Current Reporting Status Yes  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Trading Symbol albo  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   12,039,305