Fair Value Measurements. Cash Equivalents and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Fair Value Measurements, Recurring and Nonrecurring

The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows:

	December 31, 2023
	Fair Value		Level 1		Level 2		Level 3
	(in thousands)
Financial Assets:
Money market funds	$	1,032,500	$	1,032,500	$	—	$	—
Total cash equivalents	$	1,032,500	$	1,032,500	$	—	$	—
U.S. government debt securities	$	35,097	$	—	$	35,097	$	—
Total short-term marketable debt securities	$	35,097	$	—	$	35,097	$	—
Long-term marketable equity securities	$	98,002	$	98,002	$	—	$	—
Total	$	1,165,599	$	1,130,502	$	35,097	$	—
Financial Liabilities:
Contingent consideration	$	6,540	$	—	$	—	$	6,540
Total	$	6,540	$	—	$	—	$	6,540

	December 31, 2022
	Fair Value		Level 1		Level 2		Level 3
	(in thousands)
Financial Assets:
Money market funds	$	3,104	$	3,104	$	—	$	—
U.S. government debt securities	14,987		—		14,987		—
Total cash equivalents	$	18,091	$	3,104	$	14,987	$	—
U.S. government debt securities	$	869,584	$	—	$	869,584	$	—
Total short-term marketable debt securities	$	869,584	$	—	$	869,584	$	—
Long-term marketable equity securities	$	18,291	$	18,291	$	—	$	—
Total	$	905,966	$	21,395	$	884,571	$	—
Financial Liabilities:
Contingent consideration	$	6,430	$	—	$	—	$	6,430
Total	$	6,430	$	—	$	—	$	6,430

Schedule of Level 3 Activity

The following tables summarize the activities for the Level 3 financial instruments for the years ended December 31, 2023, 2022 and 2021:

	Contingent Consideration
	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Fair value — beginning of period	$	6,430	$	3,625	$	1,245
Increase in fair value	110		4,305		2,380
Settlement	—		(1,500)		—
Fair value — end of period	$	6,540	$	6,430	$	3,625

	Noncontrolling Interest Liability				Redeemable Noncontrolling Interest
	Year Ended December 31,				Year Ended December 31,
	2022		2021		2021
	(in thousands)
Fair value — beginning of period	$	78,000	$	—	$	57,100
Increase in fair value	99,785		—		27,244
Net loss for the period	—		—		(6,344)
Settlement	(177,785)		—		—
Reclassification of redeemable noncontrolling interest to noncontrolling interest liability	—		78,000		(78,000)
Fair value — end of period	$	—	$	78,000	$	—

Schedule of Cash Equivalents and Marketable Securities'

The following tables summarize the Company’s cash equivalents and marketable debt securities’ amortized costs, gross unrealized gains, gross unrealized losses and estimated fair values by significant investment category:

	December 31, 2023
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
	(in thousands)
Money market fund	$	1,032,500	$	—	$	—	$	1,032,500
U.S. government debt securities	35,108		—		(11)		35,097
Total	$	1,067,608	$	—	$	(11)	$	1,067,597

	December 31, 2022
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
	(in thousands)
Money market fund	$	3,104	$	—	$	—	$	3,104
U.S. government debt securities	901,342		8		(16,779)		884,571
Total	$	904,446	$	8	$	(16,779)	$	887,675

Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value

The following table presents the estimated fair values and gross unrealized losses of the Company's marketable debt securities that had been in an unrealized loss position as of December 31, 2022.

	December 31, 2022
	Less Than 12 Months				12 Months or Greater				Total
	Estimated Fair Value		Gross Unrealized Loss		Estimated Fair Value		Gross Unrealized Loss		Estimated Fair Value		Gross Unrealized Loss
	(in thousands)
U.S. government debt securities	$	170,975	$	(2,958)	$	685,754	$	(13,821)	$	856,729	$	(16,779)
Total	$	170,975	$	(2,958)	$	685,754	$	(13,821)	$	856,729	$	(16,779)