Summary of Significant Accounting Policies Cash, Cash Equivalents and Short-Term Investments (Policies)

12 Months Ended

Dec. 31, 2012

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash, Cash Equivalents and Short-Term Investments: Lexicon considers all highly-liquid investments with original maturities of three months or less to be cash equivalents.  As of December 31, 2012 and 2011, short-term investments consist of U.S. treasury bills and certificates of deposit. The certificates of deposits are classified as available-for-sale securities and are carried at fair value, based on quoted market prices of the securities.  The Company views its available-for-sale securities as available for use in current operations regardless of the stated maturity date of the security.  Unrealized gains and losses on such securities are reported as a separate component of stockholders’ equity.  Net realized gains and losses, interest and dividends are included in interest income.  The cost of securities sold is based on the specific identification method.