Document and Entity Information Document - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Nov. 04, 2019
Document Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Registrant Name		LEXICON PHARMACEUTICALS, INC./DE
Entity Central Index Key		0001062822
Document Type		10-Q
Document Period End Date		Sep. 30, 2019
Amendment Flag		false
Entity Emerging Growth Company		false
Entity Small Business		false
Document Fiscal Year Focus		2019
Document Fiscal Period Focus		Q3
Current Fiscal Year End Date		--12-31
Entity Current Reporting Status		Yes
Entity Filer Category		Accelerated Filer
Entity Common Stock, Shares Outstanding			106,271,927