Stock-Based Compensation (Details 6) (USD $)	9 Months Ended
Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Awards, Grants in Period	80,808
Restricted Stock Awards, Grants in Period, Weighted Average Grant Date Fair Value	$ 1.98

The weighted average grant date fair value for grants of stock bonus and restricted stock awards made during the period under equity incentive plans.

No definition available.

Name:	lxrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockBonusAndRestrictedStockGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	lxrx_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration