Stockholders' Equity, Stock-based Compensation Expense (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) Officer	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 31, 2020 USD ($)
Stock-Based Compensation [Abstract]
Stock-based compensation expense		$ 230,117	$ 146,574	$ 131,312
Cost of Products Sold [Member]
Stock-Based Compensation [Abstract]
Stock-based compensation expense		1,991	438	160
Research, Development and Patent [Member]
Stock-Based Compensation [Abstract]
Stock-based compensation expense		115,584	95,348	76,557
Selling, General and Administrative [Member]
Stock-Based Compensation [Abstract]
Stock-based compensation expense		112,542	50,788	54,595
Akcea [Member]
Stock-Based Compensation [Abstract]
Stock-based compensation expense	$ (19,100)	$ 94,800	$ 37,100	$ 44,300
Unrecognized compensation cost related to non-vested RSUs					$ 59,300
Number of executive officers terminating employment | Officer	3