v3.19.3
Cover Page - shares
9 Months Ended
Sep. 30, 2019
Nov. 05, 2019
Cover page.    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2019  
Document Transition Report false  
Entity File Number 001-37985  
Entity Registrant Name ANAPTYSBIO, INC  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 20-3828755  
Entity Address, Address Line One 10421 Pacific Center Court  
Entity Address, Address Line Two Suite 200  
Entity Address, City or Town San Diego  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92121  
City Area Code 858  
Local Phone Number 362-6295  
Title of 12(b) Security Common Stock, $0.001 par value  
Trading Symbol ANAB  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   27,133,459
Entity Central Index Key 0001370053  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Amendment Flag false