Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	RETA
Entity Registrant Name	Reata Pharmaceuticals, Inc.
Entity Central Index Key	0001358762
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity File Number	001-37785
Entity Tax Identification Number	11-3651945
Entity Address, Address Line One	5320 Legacy Drive
Entity Address, City or Town	Plano
Entity Address, State or Province	TX
Entity Address Postal Zip Code	75024
City Area Code	972
Local Phone Number	865-2219
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Class A Common Stock, Par Value $0.001 Per Share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Common Stock A
Document Information [Line Items]
Entity Common Stock Shares Outstanding		31,368,320
Common Stock B
Document Information [Line Items]
Entity Common Stock Shares Outstanding		4,909,492