Marketable Debt and Equity Securities - Equity Securities with Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Equity Securities
Equity Securities with Readily Determinable Fair Value	$ 26,885		$ 26,885		$ 36,860
Unrealized (loss) gain recognized on equity securities	(6,545)	$ 24,720	(9,974)	$ 37,701
Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	26,885		26,885		36,860
Astria/Catabasis | Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	1,920		1,920		3,449
INmune | Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	16,668		16,668		19,233
Viridian | Common Stock
Equity Securities
Equity Securities with Readily Determinable Fair Value	$ 8,297		$ 8,297		$ 14,178