Statements of Comprehensive Loss Parenthetical (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Stock-based compensation expense associated with research and development expense	$ 989	$ 1,104
Stock-based compensation expense associated with general and administrative expense	$ 846	$ 849

Stock-based compensation expense associated with general and administrative expense.

No definition available.

Name:	lxrx_StockBasedCompensationExpenseAssociatedWithGeneralAndAdministrativeExpense
Namespace Prefix:	lxrx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration