Income Taxes (Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Federal and State net operating loss carryforward	$ 240,550	$ 286,619
Foreign net operating loss carryforward	11,577	9,011
Research tax credits	27,571	23,260
Deferred revenue	668	10,121
Original discount interest	7,167	12,445
Other	16,496	17,981
Total deferred tax assets	304,029	359,437
Valuation allowance	(299,862)	(354,530)
Net deferred tax assets	4,167	4,907
Deferred tax liabilities:
Intangibles	(1,789)	(2,090)
Other	(2,378)	(2,817)
Total deferred tax liabilities	(4,167)	(4,907)
Net deferred tax assets	$ 0	$ 0