Fair Value Measurements - Schedule of Fair Value of Financial Assets (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
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	$ 278,396		$ 278,396		$ 221,382
Marketable Securities, Fair Value	2,378,899		2,378,899		2,742,571
Total Financial Assets, Fair Value	2,691,310		2,691,310		3,013,121
Unrealized gain (loss) on equity investments	(5,084)	$ 0	23,413	$ 0
Fair Value to Amortized Cost
Amortized Cost	2,415,312		2,415,312		2,748,697
Unrealized Gains	7		7		144
Unrealized Losses	(36,420)		(36,420)		(6,270)
Fair Value	2,378,899		2,378,899		2,742,571
Level I
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	274,754		274,754		221,382
Total Financial Assets, Fair Value	1,377,823		1,377,823		1,283,429
Level II
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	3,642		3,642		0
Total Financial Assets, Fair Value	1,313,487		1,313,487		1,729,692
Level III
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	0		0		0
Total Financial Assets, Fair Value	0		0		0
Commercial paper
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	18,462		18,462		141,274
Fair Value to Amortized Cost
Amortized Cost	18,462		18,462		141,274
Unrealized Gains	0		0		0
Unrealized Losses	0		0		0
Fair Value	18,462		18,462		141,274
Commercial paper | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Commercial paper | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	18,462		18,462		141,274
Fair Value to Amortized Cost
Fair Value	18,462		18,462		141,274
Commercial paper | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Certificate of deposits
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	13,030		13,030		44,931
Fair Value to Amortized Cost
Fair Value	13,030		13,030		44,931
Certificate of deposits | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Certificate of deposits | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	13,030		13,030		44,931
Fair Value to Amortized Cost
Fair Value	13,030		13,030		44,931
Certificate of deposits | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
U.S. government notes
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,082,084		1,082,084		1,057,810
Fair Value to Amortized Cost
Amortized Cost	1,098,360		1,098,360		1,060,716
Unrealized Gains	0		0		3
Unrealized Losses	(16,276)		(16,276)		(2,909)
Fair Value	1,082,084		1,082,084		1,057,810
U.S. government notes | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,082,084		1,082,084		1,057,810
Fair Value to Amortized Cost
Fair Value	1,082,084		1,082,084		1,057,810
U.S. government notes | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
U.S. government notes | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,066,585		1,066,585		1,252,226
Fair Value to Amortized Cost
Amortized Cost	1,083,803		1,083,803		1,255,149
Unrealized Gains	6		6		105
Unrealized Losses	(17,224)		(17,224)		(3,028)
Fair Value	1,066,585		1,066,585		1,252,226
Corporate bonds | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Corporate bonds | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,066,585		1,066,585		1,252,226
Fair Value to Amortized Cost
Fair Value	1,066,585		1,066,585		1,252,226
Corporate bonds | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Agency securities
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	211,768		211,768		291,261
Fair Value to Amortized Cost
Amortized Cost	214,687		214,687		291,558
Unrealized Gains	1		1		36
Unrealized Losses	(2,920)		(2,920)		(333)
Fair Value	211,768		211,768		291,261
Agency securities | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Agency securities | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	211,768		211,768		291,261
Fair Value to Amortized Cost
Fair Value	211,768		211,768		291,261
Agency securities | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Marketable equity securities
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	16,727		16,727		0
Fair value of securities reclassified			8,300
Unrealized gain (loss) on equity investments	(5,100)		8,400
Fair Value to Amortized Cost
Fair Value	16,727		16,727		0
Marketable equity securities | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	16,727		16,727		0
Fair Value to Amortized Cost
Fair Value	16,727		16,727		0
Marketable equity securities | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Marketable equity securities | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Marketable Securities
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	2,408,656		2,408,656		2,787,502
Fair Value to Amortized Cost
Fair Value	2,408,656		2,408,656		2,787,502
Marketable Securities | Level I
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,098,811		1,098,811		1,057,810
Fair Value to Amortized Cost
Fair Value	1,098,811		1,098,811		1,057,810
Marketable Securities | Level II
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	1,309,845		1,309,845		1,729,692
Fair Value to Amortized Cost
Fair Value	1,309,845		1,309,845		1,729,692
Marketable Securities | Level III
Assets, Fair Value Disclosure [Abstract]
Marketable Securities, Fair Value	0		0		0
Fair Value to Amortized Cost
Fair Value	0		0		0
Money market funds - restricted
Assets, Fair Value Disclosure [Abstract]
Other Assets, Fair Value	4,258		4,258		4,237
Money market funds - restricted | Level I
Assets, Fair Value Disclosure [Abstract]
Other Assets, Fair Value	4,258		4,258		4,237
Money market funds - restricted | Level II
Assets, Fair Value Disclosure [Abstract]
Other Assets, Fair Value	0		0		0
Money market funds - restricted | Level III
Assets, Fair Value Disclosure [Abstract]
Other Assets, Fair Value	0		0		0
Money market funds
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	274,754		274,754		221,382
Money market funds | Level I
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	274,754		274,754		221,382
Money market funds | Level II
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	0		0		0
Money market funds | Level III
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	0		0		0
Commercial paper
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	3,642		3,642		0
Commercial paper | Level I
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	0		0		0
Commercial paper | Level II
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	3,642		3,642		0
Commercial paper | Level III
Assets, Fair Value Disclosure [Abstract]
Cash Equivalents, Fair Value	$ 0		$ 0		$ 0