Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2019

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 December 31, 2019 and 2018 (in thousands):

	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
December 31, 2019
Assets:
Cash and cash equivalents	$	327,214	$	311,245	$	15,969	$	—
Marketable securities:
U.S. government agency securities and treasuries	635,936		—		635,936		—
Certificates of deposit	960		—		960		—
Commercial paper	74,378		—		74,378		—
Corporate bonds	186,608		—		186,608		—
Equity securities	12,870		12,870		—		—
Total assets	$	1,237,966	$	324,115	$	913,851	$	—
Liabilities:
Contingent consideration	$	7,977	$	—	$	—	$	7,977
Total liabilities	$	7,977	$	—	$	—	$	7,977
December 31, 2018
Assets:
Cash and cash equivalents	$	402,579	$	348,638	$	53,941	$	—
Marketable securities:
U.S. government agency securities	1,457,601		—		1,457,601		—
Certificates of deposit	9,080		—		9,080		—
Equity securities	22,167		22,167		—		—
Total assets	$	1,891,427	$	370,805	$	1,520,622	$	—
Liabilities:
Contingent consideration	$	5,230	$	—	$	—	$	5,230
Total liabilities	$	5,230	$	—	$	—	$	5,230

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):

	Year ended December 31,
	2019		2018
Beginning balance	$	5,230	$	2,231
Additions	—		—
Changes in fair value	2,747		2,999
Payments	—		—
Ending balance	$	7,977	$	5,230