Income Taxes, Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets [Abstract]
Net operating loss carryovers	$ 89,717	$ 89,717	$ 153,575
R&D credits	313,652	313,652	240,290
Deferred revenue	27,381	27,381	54,302
Stock-based compensation	61,027	61,027	40,090
Intangible and capital assets	49,007	49,007	672
Other	8,275	8,275	12,164
Total deferred tax assets	549,059	549,059	501,093
Deferred Tax Liabilities [Abstract]
Convertible debt	(24,018)	(24,018)	(32,391)
Net deferred tax asset	525,041	525,041	468,702
Valuation allowance	(234,245)	(234,245)	(468,702)
Total net deferred tax assets and liabilities	290,796	290,796	0
One-time non-cash tax benefit related to reversal of valuation allowance	$ 332,100	$ (277,924)	$ (86,296)	$ 46,402
Utilization period for net operating loss carryforwards and tax credit carryforwards		3 years
Decrease in valuation allowance		$ (234,500)