Goodwill (Details) (USD $) In Millions, unless otherwise specified	Jul. 30, 2010	Jul. 12, 2001
Goodwill
Coelacanth Goodwill		$ 25.8lxrx_CoelacanthGoodwill
Coelacanth Purchase Price		36.0lxrx_CoelacanthPurchasePrice
Symphony Icon Goodwill	$ 18.7lxrx_SymphonyIconGoodwill

On July 12, 2001, Lexicon completed the acquisition of Coelacanth Corporation in a merger. Goodwill associated with the acquisition of $25.8 million, which represents the excess of the $36.0 million purchase price over the fair value of the underlying net identifiable assets, was assigned to the consolidated entity, Lexicon. This represents the purchase price.

No definition available.

Name:	lxrx_CoelacanthPurchasePrice
Namespace Prefix:	lxrx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant