Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2017

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, 2017 and December 31, 2016 (in thousands):

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
June 30, 2017
Assets:
Cash and cash equivalents	$	686,334	$	686,334			$	—
Marketable securities:
U.S. government agency securities and treasuries		507,361		—		507,361		—
Certificates of deposit		3,364		—		3,364		—
Total assets	$	1,197,059	$	686,334	$	510,725	$	—
Liabilities:
Contingent consideration	$	3,219	$	—	$	—	$	3,219
Total liabilities	$	3,219	$	—	$	—	$	3,219
December 31, 2016
Assets:
Cash and cash equivalents	$	278,887	$	278,887	$	—	$	—
Marketable securities:
U.S. government agency securities and treasuries		599,460		—		599,460		—
Certificates of deposit		6,483		—		6,483		—
Total assets	$	884,830	$	278,887	$	605,943	$	—
Liabilities:
Contingent consideration	$	7,756	$	—	$	—	$	7,756
Total liabilities	$	7,756	$	—	$	—	$	7,756

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):

	For the Six Months Ended
	June 30, 2017
Fair value, beginning of period	$	7,756
Additions		—
Changes in fair value		463
Reclassification to accrued expenses		(5,000	)
Payments		—
Fair value, end of balance	$	3,219