Fair value of financial instruments (Tables)

6 Months Ended

Jun. 30, 2017

Marketable Securities

Schedule of fair value of assets and liabilities 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 as of June 30, 2017 (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)		June 30, 2017
Cash and cash equivalents	$	451,754	$	—	$	—	$	451,754
Debt securities (corporate and government)		—		156,852		—		156,852
Long term investments (Note 9)		76,268		68,157		—		144,425
Total assets	$	528,022	$	225,009	$	—	$	753,031

The following fair value hierarchy table presents information about each major category of our financial liabilities measured at fair value on a recurring basis as of June 30, 2017 (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)		June 30, 2017
Contingent consideration (Note 3)	$	—	$	—	$	306,000	$	306,000
Total liabilities	$	—	$	—	$	306,000	$	306,000

Schedule of rollforward of Level 3 liabilities

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

	Level 3
Balance at January 1, 2017	$	301,000
Contingent consideration earned during the period but not yet paid		(5,073)
Payments made during the period		(4,356)
Change in fair value of contingent consideration		14,429
Balance at June 30, 2017	$	306,000

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 as of December 31, 2016 (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, 2016
Cash and cash equivalents	$	652,343	$	—	$	—	$	652,343
Debt securities (corporate and government)		—		156,203		—		156,203
Long term investment (Note 9)		31,987		—		—		31,987
Total assets	$	684,330	$	156,203	$	—	$	840,533

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 as of December 31, 2016 (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, 2016
Contingent consideration (Note 3)	$	—	$	—	$	301,000	$	301,000
Total liabilities	$	—	$	—	$	301,000	$	301,000

Summary of marketable securities portfolio

			Net		Net
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		Fair Value
	(in thousands)
June 30, 2017
Debt securities (corporate and government)	$	157,111	$	—	$	(259)	$	156,852
December 31, 2016
Debt securities (corporate and government)	$	156,330	$	—	$	(127)	$	156,203