Marketable Securities and Fair Value Measurements

3 Months Ended

Mar. 31, 2020

Investments, All Other Investments [Abstract]

Marketable Securities and Fair Value Measurements

The following tables present marketable securities by security type:


As of March 31, 2020 (in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Commercial paper (due within one year)	$	270,577	$	174	$	(115)	$	270,636
U.S. Government securities (due within one year)	134,685		608		—		135,293
Certificates of deposit (due within one year)	45,836		84		—		45,920
Other debt securities (due within one year)	9,987		12		—		9,999
Total	$	461,085	$	878	$	(115)	$	461,848


As of December 31, 2019 (in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Commercial paper (due within one year)	$	314,292	$	74	$	(23)	$	314,343
U.S. Government securities (due within one year)	78,612		48		(3)		78,657
Certificates of deposit (due within one year)	66,241		17		(2)		66,256
Total	$	459,145	$	139	$	(28)	$	459,256

The following tables present information about the Company's financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values:


As of March 31, 2020 (in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	—	$	93,156	$	—	$	93,156
U.S. Government Securities	—		21,900		—		21,900
Certificates of deposit	—		17,508		—		17,508
Commercial paper	—		16,495		—		16,495
Marketable securities:
Commercial paper	—		270,636		—		270,636
U.S. Government securities	—		135,293		—		135,293
Certificates of deposit	—		45,920		—		45,920
Other debt securities	—		9,999		—		9,999
Total	$	—	$	610,907	$	—	$	610,907


As of December 31, 2019 (in thousands)	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	—	$	28,192	$	—	$	28,192
Certificates of deposit	—		20,500		—		20,500
Marketable securities:
Commercial paper	—		314,343		—		314,343
U.S. Government securities	—		78,657		—		78,657
Certificates of deposit	—		66,256		—		66,256
Total	$	—	$	507,948	$	—	$	507,948

The table above excludes certificates of deposit totaling $2.1 million and $1.5 million as of March 31, 2020 and December 31, 2019, respectively, that the Company held to secure a letter of credit associated with a lease and to secure a credit card account. The Company increased its credit card limit and corresponding certificate of deposit in the first quarter of 2020. The certificates of deposit are Level 2 instruments and are measured at carrying value in the consolidated balance sheets in long-term investment—restricted and approximate fair value. For additional information on the letter of credit associated with a lease, please read Note 6, Leases, to the consolidated financial statements in the Company's Form 10-K for the year ended December 31, 2019.

The fair value of Level 2 instruments classified as cash equivalents and marketable securities were determined through third-party pricing services. The pricing services use many observable market inputs to determine value, including reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates, and other industry and economic events.