Summary of Significant Accounting Policies Equity Incentive Awards (Tables)

6 Months Ended

Jun. 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
June 30, 2018:
Employees	59	%	2.5	%	4	—	%
Officers and non-employee directors	63	%	2.8	%	8	—	%
June 30, 2017:
Employees	61	%	1.8	%	4	—	%
Officers and non-employee directors	69	%	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	1,541		9.80
Exercised	(50	)	7.83
Expired	(216	)	14.28
Forfeited	(132	)	12.54
Outstanding at June 30, 2018	6,104		10.71
Exercisable at June 30, 2018	3,368		$	10.85

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	(102	)	12.20
Outstanding at June 30, 2018	1,382		$	10.74

Share-basedGranttoBOD

During the six months ended June 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