Income Taxes, Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets [Abstract]
Net operating loss carryovers	$ 153,575	$ 194,372
R&D credits	240,290	193,845
Deferred revenue	42,055	54,203
Stock-based compensation	40,090	48,209
Intangible and capital assets	672	0
Other	12,164	26,228
Total deferred tax assets	488,846	516,857
Deferred Tax Liabilities [Abstract]
Convertible debt	(32,391)	(62,669)
Intangible and capital assets	0	(2,030)
Net deferred tax asset	456,455	452,158
Valuation allowance	(456,455)	(452,158)
Total net deferred tax assets and liabilities	0	$ 0
Impact of change in tax rate on deferred tax assets under the Tax Act	107,300
Tax benefit related to cumulative prior year AMT tax credit carryovers under the Tax Act	$ (7,700)