v3.21.2
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2021
Aug. 09, 2021
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Document Period End Date Jun. 30, 2021  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q2  
Trading Symbol ARPO  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Registrant Name Aerpio Pharmaceuticals, Inc.  
Entity Central Index Key 0001422142  
Entity Common Stock, Shares Outstanding   47,660,492
Entity Shell Company false  
Entity Current Reporting Status Yes  
Entity File Number 001-38560  
Entity Tax Identification Number 61-1547850  
Entity Address, Address Line One c/o 10663 Loveland  
Entity Address, Address Line Two Madeira Road #168  
Entity Address, City or Town Loveland  
Entity Address, State or Province OH  
Entity Address, Postal Zip Code 45140  
City Area Code 513  
Local Phone Number 985-1920  
Entity Interactive Data Current Yes  
Title of 12(b) Security Common stock, $0.0001 par value per share  
Security Exchange Name NASDAQ  
Entity Incorporation, State or Country Code DE  
Document Quarterly Report true  
Document Transition Report false  
Former Address [Member]    
Document Information [Line Items]    
Entity Address, Address Line One 9987 Carver Road  
Entity Address, City or Town Cincinnati  
Entity Address, State or Province OH  
Entity Address, Postal Zip Code 45242