Organization and Significant Accounting Policies, Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Loss [Roll Forward]
Balance		$ 743,282	$ 1,577,459	$ 1,100,623
Adjustments to other comprehensive loss from purchase of noncontrolling interest of Akcea Therapeutics, Inc.		0	(127)	0
Net other comprehensive loss for the period		(11,597)	4,219	6,726
Balance		771,737	743,282	1,577,459
Income tax expense (benefit) included in other comprehensive loss		0	0	(1,400)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Balance		(21,071)	(25,290)	(32,016)
Balance		(32,668)	(21,071)	(25,290)
Unrealized Gains (Losses) on Securities [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Other comprehensive loss before reclassifications, net of tax	[1]	(11,486)	3,729	6,633
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Other comprehensive loss before reclassifications, net of tax		$ (111)	$ 617	$ 93

[1] We did not have tax expense included in our other comprehensive loss for the years ended December 31, 2021 and 2020. For the year ended December 31, 2019, we had a tax benefit of $1.4 million included in other comprehensive loss.