Fair value of financial instruments (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value of Financial Instruments

Summary of marketable securities portfolio

The following is a summary of our marketable security portfolio for the periods presented (in thousands):

			Net
	Amortized		Unrealized		Estimated
	Cost		Gains		Fair Value
December 31, 2020
Debt securities (government)	$	288,199	$	170	$	288,369
December 31, 2019
Debt securities (government)	$	284,795	$	75	$	284,870

Schedule of fair value of assets measured on recurring basis

The following fair value hierarchy table presents information about each major category of our financial assets measured at fair value on a recurring basis (in thousands):

	Fair Value Measurement at Reporting Date Using:
	Quoted Prices in		Significant Other		Significant
	Active Markets for		Observable		Unobservable
	Identical Assets		Inputs		Inputs		Balance as of
	(Level 1)		(Level 2)		(Level 3)		December 31, 2020
Cash and cash equivalents	$	1,513,008	$	—	$	—	$	1,513,008
Debt securities (government)		—		288,369		—		288,369
Long term investments (Note 6)		222,301		—		—		222,301
Total assets	$	1,735,309	$	288,369	$	—	$	2,023,678

	Fair Value Measurement at Reporting Date Using:
	Quoted Prices in		Significant Other		Significant
	Active Markets for		Observable		Unobservable
	Identical Assets		Inputs		Inputs		Balance as of
	(Level 1)		(Level 2)		(Level 3)		December 31, 2019
Cash and cash equivalents	$	1,832,684	$	—	$	—	$	1,832,684
Debt securities (government)		—		284,870		—		284,870
Long term investments (Note 6)		133,657		—		—		133,657
Total assets	$	1,966,341	$	284,870	$	—	$	2,251,211

Schedule of fair value of liabilities measured on recurring basis

The following fair value hierarchy table presents information about each major category of our financial liabilities measured at fair value on a recurring basis (in thousands):

	Fair Value Measurement at Reporting Date Using:
	Quoted Prices in		Significant Other		Significant
	Active Markets for		Observable		Unobservable
	Identical Liabilities		Inputs		Inputs		Balance as of
	(Level 1)		(Level 2)		(Level 3)		December 31, 2020
Acquisition-related contingent consideration	$	—	$	—	$	266,000	$	266,000
Total liabilities	$	—	$	—	$	266,000	$	266,000

	Fair Value Measurement at Reporting Date Using:
	Quoted Prices in		Significant Other		Significant
	Active Markets for		Observable		Unobservable
	Identical Liabilities		Inputs		Inputs		Balance as of
	(Level 1)		(Level 2)		(Level 3)		December 31, 2019
Acquisition-related contingent consideration	$	—	$	—	$	277,000	$	277,000
Total liabilities	$	—	$	—	$	277,000	$	277,000

Schedule of roll forward of Level 3 liabilities

The following is a roll forward of our Level 3 liabilities (in thousands):

	2020		2019
Balance at January 1,	$	277,000	$	287,001
Contingent consideration earned during the period but not yet paid		(9,595)		(23,012)
Payments made during the period		(24,790)		(6,671)
Change in fair value of contingent consideration		23,385		19,682
Balance at December 31,	$	266,000	$	277,000