Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2018	Oct. 29, 2018
Document Information [Line Items]
Entity Registrant Name	LEXICON PHARMACEUTICALS, INC./DE
Entity Central Index Key	0001062822
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		105,925,402