Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2016

Fair Value Disclosures [Abstract]

Recorded Amount of Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table sets forth the Company’s assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2016 and December 31, 2015 (in thousands):

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
June 30, 2016
Assets:
Cash and cash equivalents	$	222,629	$	222,629	$	—	$	—
Marketable securities:
U.S. government agency securities and treasuries		550,117		—		550,117		—
Certificates of deposit		6,256		—		6,256		—
Total assets	$	779,002	$	222,629	$	556,373	$	—
Liabilities:
Contingent consideration	$	6,082	$	—	$	—	$	6,082
Total liabilities	$	6,082	$	—	$	—	$	6,082
December 31, 2015
Assets:
Cash and cash equivalents	$	164,269	$	158,269	$	6,000	$	—
Marketable securities:
U.S. government agency securities and treasuries		687,147		—		687,147		—
Certificates of deposit		14,347		—		14,347		—
Total assets	$	865,763	$	158,269	$	707,494	$	—
Liabilities:
Contingent consideration	$	8,665	$	—	$	—	$	8,665
Total liabilities	$	8,665	$	—	$	—	$	8,665

Roll-Forward of Fair Value of the Company's Contingent Consideration Obligations

The table below provides a roll-forward of fair value of the Company’s contingent consideration obligations, which include Level 3 inputs (in thousands):

	Six Months Ended
	June 30, 2016
Beginning balance	$	8,665
Additions		—
Changes in fair value		2,417
Payments		(5,000	)
Ending balance	$	6,082