Fair value measurements (Tables)

3 Months Ended

Mar. 31, 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 March 31, 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)
March 31, 2016
Assets:
Cash and cash equivalents	$	192,588	$	187,588	$	5,000	$	—
Marketable securities:
U.S. government agency securities and treasuries		625,624		—		625,624		—
Certificates of deposit		8,653		—		8,653		—
Total assets	$	826,865	$	187,588	$	639,277	$	—
Liabilities:
Contingent consideration	$	9,678	$	—	$	—	$	9,678
Total liabilities	$	9,678	$	—	$	—	$	9,678
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):

	Three Months Ended
	March 31, 2016
Beginning balance	$	8,665
Additions		—
Changes in fair value		1,013
Payments		—
Ending balance	$	9,678