Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets and Liabilities
Deferred Tax Assets, Operating Loss Carryforwards	$ 193,270	$ 206,789
Deferred Tax Assets, Tax Credit Carryforwards, Research	46,306	47,087
Deferred Tax Assets, Tax Credit Carryforwards, Orphan Drug	24,524	24,524
Deferred Tax Assets, In Process Research and Development	58,596	71,047
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	5,340	4,641
Deferred Tax Assets, Deferred Income	0	5,458
Deferred Tax Assets, Section 163j_LXRX		3,625
Deferred Tax Assets, Other	5,533	6,044
Deferred Tax Assets, Gross	333,569	369,215
Deferred Tax Liability Related to Acquisition of Symphony Icon	(4,140)	(10,525)
Deferred Tax Liabilities, Other	(3)	(2)
Deferred Tax Liabilities, Gross	(4,143)	(10,527)
Deferred Tax Assets, Valuation Allowance	(329,426)	(364,702)
Deferred Tax Liabilities, Net	0	(6,014)
Income Tax Benefit	$ (6,014)	$ 0	$ (12,661)