Income Taxes Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets
Net operating loss carryforwards	$ 45,296	$ 49,096
Research and development credits	33,484	33,484
Marketable securities	19,266	0
Compensatory and other accruals	1,827	2,698
Unrealized losses on investments	0	5,265
Intangible assets	6,847	819
Foreign tax credits	0	201
Other, net	6,152	3,725
Gross deferred tax assets	112,872	95,288
Deferred tax liabilities:
Unrealized gains on investments	97	0
Fixed assets	20,073	19,128
Gross deferred tax liabilities	20,170	19,128
Net deferred tax asset before valuation allowance	92,702	76,160
Valuation Allowance	(93,439)	(78,018)
Net deferred tax liability	$ (737)	$ (1,858)