Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	$ 656,704	$ 90,224
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	0	(1)
Estimated Fair Value	656,704	90,224
Cash Equivalents | Money Market Funds | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	656,524	48,359
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	656,524	48,359
Cash Equivalents | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	180	1,138
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	180	1,138
Cash Equivalents | US Government and Agencies Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost		40,727
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses		(1)
Estimated Fair Value		40,727
Short-term Marketable Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	177,682	253,435
Gross Unrealized Holding Gains	25	30
Gross Unrealized Holding Losses	(11)	(7)
Estimated Fair Value	177,696	253,458
Short-term Marketable Securities | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	52,776	8,798
Gross Unrealized Holding Gains	4	0
Gross Unrealized Holding Losses	(11)	(2)
Estimated Fair Value	52,769	8,796
Short-term Marketable Securities | US Government and Agencies Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	124,906	244,637
Gross Unrealized Holding Gains	21	30
Gross Unrealized Holding Losses	0	(5)
Estimated Fair Value	124,927	244,662
Long-term Marketable Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	77,935	33,724
Gross Unrealized Holding Gains	7	7
Gross Unrealized Holding Losses	(8)	0
Estimated Fair Value	77,934	33,731
Long-term Marketable Securities | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	3,471
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	(4)
Estimated Fair Value	3,467
Long-term Marketable Securities | US Government and Agencies Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	74,464	33,724
Gross Unrealized Holding Gains	7	7
Gross Unrealized Holding Losses	(4)	0
Estimated Fair Value	74,467	33,731
Financial Assets
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	912,321	377,383
Gross Unrealized Holding Gains	32	38
Gross Unrealized Holding Losses	(19)	(8)
Estimated Fair Value	912,334	377,413
Short-term Financial Liabilities | Success Payment Liabilities | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	5,000
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	5,000
Long-term Financial Liabilities | Contingent Consideration | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	140,457	121,901
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	140,457	121,901
Long-term Financial Liabilities | Success Payment Liabilities | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	103,963	76,494
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	103,963	76,494
Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	249,420	198,395
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	$ 249,420	$ 198,395