Fair Value Measurements. Cash Equivalents and Marketable Securities - Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - Fair value, measurements, recurring - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 1,032,500	$ 18,091
Total short-term marketable debt securities	35,097	869,584
Long-term marketable debt securities	98,002	18,291
Total financial assets	1,165,599	905,966
Contingent consideration	6,540	6,430
Total financial liabilities	6,540	6,430
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	1,032,500	3,104
Total short-term marketable debt securities	0	0
Long-term marketable debt securities	98,002	18,291
Total financial assets	1,130,502	21,395
Contingent consideration	0	0
Total financial liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	14,987
Total short-term marketable debt securities	35,097	869,584
Long-term marketable debt securities	0	0
Total financial assets	35,097	884,571
Contingent consideration	0	0
Total financial liabilities	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Total short-term marketable debt securities	0	0
Long-term marketable debt securities	0	0
Total financial assets	0	0
Contingent consideration	6,540	6,430
Total financial liabilities	6,540	6,430
U.S. government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term marketable debt securities	35,097	869,584
U.S. government debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term marketable debt securities	0	0
U.S. government debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term marketable debt securities	35,097	869,584
U.S. government debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term marketable debt securities	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	1,032,500	3,104
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	1,032,500	3,104
Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	0	0
Money market funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 0	0
U.S. government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		14,987
U.S. government debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		0
U.S. government debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		14,987
U.S. government debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		$ 0