Document And Entity Information - shares
6 Months Ended
Jun. 30, 2019
Aug. 09, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Trading Symbol ALDX  
Entity Registrant Name ALDEYRA THERAPEUTICS, INC.  
Entity Central Index Key 0001341235  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Emerging Growth Company true  
Entity Small Business true  
Entity Ex Transition Period false  
Entity Common Stock, Shares Outstanding   27,578,247
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity File Number 001-36332  
Entity Tax Identification Number 201968197  
Entity Address, Address Line One 131 Hartwell Avenue  
Entity Address, Address Line Two Suite 320  
Entity Address, City or Town Lexington  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02421  
City Area Code (781)  
Local Phone Number 761-4904