Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	$ 379,457	$ 90,224
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	0	(1)
Estimated Fair Value	379,457	90,224
Cash Equivalents | Money Market Funds | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	379,336	48,359
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	379,336	48,359
Cash Equivalents | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	121	1,138
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	121	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	170,042	253,435
Gross Unrealized Holding Gains	22	30
Gross Unrealized Holding Losses	(23)	(7)
Estimated Fair Value	170,041	253,458
Short-term Marketable Securities | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	93,504	8,798
Gross Unrealized Holding Gains	4	0
Gross Unrealized Holding Losses	(23)	(2)
Estimated Fair Value	93,485	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	76,538	244,637
Gross Unrealized Holding Gains	18	30
Gross Unrealized Holding Losses	0	(5)
Estimated Fair Value	76,556	244,662
Long-term Marketable Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	262,482	33,724
Gross Unrealized Holding Gains	24	7
Gross Unrealized Holding Losses	(105)	0
Estimated Fair Value	262,401	33,731
Long-term Marketable Securities | Corporate Debt Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	35,621
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	(24)
Estimated Fair Value	35,597
Long-term Marketable Securities | US Government and Agencies Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	226,861	33,724
Gross Unrealized Holding Gains	24	7
Gross Unrealized Holding Losses	(81)	0
Estimated Fair Value	226,804	33,731
Financial Assets
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	811,981	377,383
Gross Unrealized Holding Gains	46	38
Gross Unrealized Holding Losses	(128)	(8)
Estimated Fair Value	811,899	377,413
Short-term Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	48,459
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	48,459
Short-term Financial Liabilities | Contingent Consideration | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	43,459
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	43,459
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
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	217,714
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Estimated Fair Value	217,714
Long-term Financial Liabilities | Contingent Consideration | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	88,522	121,901
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	88,522	121,901
Long-term Financial Liabilities | Success Payment Liabilities | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	129,192	76,494
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	129,192	76,494
Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	266,173	198,395
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	$ 266,173	$ 198,395