Agreements with Invus, L.P.	12 Months Ended
Dec. 31, 2011
Agreements with Invus, L.P. [Abstract]
Agreements With Invus, L.P.	Agreements with Invus, L.P. and Its Affiliates In June 2007, Lexicon entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with Invus, L.P. under which Invus, L.P. purchased 50,824,986 shares of the Company’s common stock in August 2007. In November 2011, Invus, L.P. and its affiliate Invus C.V. (collectively “Invus”) exercised their rights under the Securities Purchase Agreement to require Lexicon to conduct a pro rata rights offering to its stockholders. In December 2011, Lexicon completed the rights offering of 142,492,883 shares of its common stock at a price of $1.13 per share, resulting in net proceeds of $160.6 million, after offering expenses of $0.4 million. Invus and its affiliates purchased 115,044,247 of these shares, resulting in Invus and its affiliates owning greater than 50% of Lexicon's outstanding common stock. All of the net proceeds of this rights offering are reflected as issuance of common stock in the accompanying financial statements. The rights offering exercise price of $1.13 was less than the closing price of Lexicon's common stock on the last day of the offering period of $1.14; however, if considered a bonus element, this difference in price did not result in a change in earnings per share from what was originally reported in previous periods. In connection with the Securities Purchase Agreement, Lexicon also entered into a Stockholders’ Agreement with Invus, L.P. under which Invus has specified rights with respect to designation of directors, participation in future equity issuances by the Company and certain consent rights.

Agreements with Invus, L.P. and Its Affiliates

In June 2007, Lexicon entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with Invus, L.P. under which Invus, L.P. purchased 50,824,986 shares of the Company’s common stock in August 2007. In November 2011, Invus, L.P. and its affiliate Invus C.V. (collectively “Invus”) exercised their rights under the Securities Purchase Agreement to require Lexicon to conduct a pro rata rights offering to its stockholders. In December 2011, Lexicon completed the rights offering of 142,492,883 shares of its common stock at a price of $1.13 per share, resulting in net proceeds of $160.6 million, after offering expenses of $0.4 million. Invus and its affiliates purchased 115,044,247 of these shares, resulting in Invus and its affiliates owning greater than 50% of Lexicon's outstanding common stock. All of the net proceeds of this rights offering are reflected as issuance of common stock in the accompanying financial statements. The rights offering exercise price of $1.13 was less than the closing price of Lexicon's common stock on the last day of the offering period of $1.14; however, if considered a bonus element, this difference in price did not result in a change in earnings per share from what was originally reported in previous periods.

In connection with the Securities Purchase Agreement, Lexicon also entered into a Stockholders’ Agreement with Invus, L.P. under which Invus has specified rights with respect to designation of directors, participation in future equity issuances by the Company and certain consent rights.