Summary of Significant Accounting Policies Equity Incentive Awards (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Expected Volatility		Risk-free Interest Rate		Expected Term	Dividend Rate
September 30, 2018:
Employees	58	%	2.6	%	4	—	%
Officers and non-employee directors	63	%	2.8	%	8	—	%
September 30, 2017:
Employees	61	%	1.7	%	4	—	%
Officers and non-employee directors	70	%	2.2	%	8	—	%

Share-based Compensation, Stock Options, Activity [Table Text Block]

	Options		Weighted Average Exercise Price
	(in thousands)
Outstanding at December 31, 2017	4,961		$	11.17
Granted	1,811		10.08
Exercised	(70	)	7.93
Expired	(229	)	14.30
Forfeited	(279	)	11.61
Outstanding at September 30, 2018	6,194		10.75
Exercisable at September 30, 2018	3,521		$	10.80

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Shares		Weighted Average Grant Date Fair Value
	(in thousands)
Outstanding at December 31, 2017	946		$	10.50
Granted	872		9.79
Vested	(334	)	9.85
Forfeited	(178	)	10.58
Outstanding at September 30, 2018	1,306		$	10.18

Share-basedGranttoBOD

During the nine months ended September 30, 2018, Lexicon granted its non-employee directors 20,512 shares of restricted stock awards. The restricted stock awards had a weighted average grant date fair value of $7.80 per share and vested immediately