Collaboration and License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020
Collaboration and License Agreements [Abstract]
Sanofi termination cash payment	$ 26,000
Ipsen Revenue Recognized				$ 300
lxrx_sanofi initial cash payment	$ 26,000	$ 26,000
Settlement Payment from Termination			$ 208,000