Other Capital Stock Agreements (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
Nov. 30, 2014	Oct. 31, 2012
Schedule of Capitalization, Equity
Stock Issued During Period, Shares, New Issues	55,608,930	17,500,000
Offering Price Per Share	$ 1.005lxrx_OfferingPricePerShare	$ 2.25lxrx_OfferingPricePerShare
Net Proceeds From Stock Offering	$ 201.9lxrx_NetProceedsFromStockOffering	$ 37.1lxrx_NetProceedsFromStockOffering
Payments of Underwriting Discounts and Commissions	3.4	2.0
Payments of Stock Issuance Costs	$ 0.6us-gaap_PaymentsOfStockIssuanceCosts	$ 0.2us-gaap_PaymentsOfStockIssuanceCosts
Stock Issued During Period to Invus, Shares	149,253,731	3,000,000

The net proceeds from stock offerings, after deducting fees and expenses.

No definition available.

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- Definition

Lexicon completed the public offering and sale of shares of its common stock. This represents the price per share.

+ References

No definition available.

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- Definition

The cash outflow for costs incurred related to underwriting discounts and commissions incurred directly with the issuance of an equity security.

+ References

No definition available.

+ Details

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- Definition

Number of new stock issued during the period to Invus, L.P. and its affiliates.

+ References

No definition available.

+ Details

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- Definition

The cash outflow for cost incurred directly with the issuance of an equity security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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