Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Aug. 06, 2019
Document and Entity Information [Abstract]    
Amendment Flag false  
Document Type 10-Q  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Document Quarterly Report true  
Entity Central Index Key 0001567514  
Document Transition Report false  
Current Fiscal Year End Date --12-31  
Document Period End Date Jun. 30, 2019  
Entity Registrant Name Intra-Cellular Therapies, Inc.  
Trading Symbol ITCI  
Entity Filer Category Large Accelerated Filer  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Interactive Data Current Yes  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity File Number 001-36274  
Entity Tax Identification Number 36-4742850  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 430 East 29th Street  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10016  
City Area Code 646  
Local Phone Number 440-9333  
Title of 12(b) Security Common Stock  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   55,173,222