Fair Value Measurements

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

Assets and liabilities measured at fair value at each balance sheet date are as follows (in thousands):

	December 31, 2019
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	54,163	$	—	$	—	$	54,163
U.S. government treasuries	15,989		—		—		15,989
Short-term marketable securities:
U.S. government treasuries	250,070		—		—		250,070
U.S. government agency securities	—		2,000		—		2,000
Corporate debt securities	—		53,479		—		53,479
Commercial paper	—		30,358		—		30,358
Long-term marketable securities:
U.S. government treasuries	13,869		—		—		13,869
Corporate debt securities	—		26,017		—		26,017
Foreign currency derivative contracts	—		85		—		85
Total	$	334,091	$	111,939	$	—	$	446,030
Liabilities:
Foreign currency derivative contracts	$	—	$	8	$	—	$	8
Total	$	—	$	8	$	—	$	8

	December 31, 2018
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	42,225	$	—	$	—	$	42,225
U.S. government treasuries	1,499		—		—		1,499
Commercial paper	—		9,979		—		9,979
Short-term marketable securities:
U.S. government treasuries	219,754		—		—		219,754
U.S. government agency securities	—		73,151		—		73,151
Corporate debt securities	—		71,675		—		71,675
Commercial paper	—		22,594		—		22,594
Long-term marketable securities:
U.S. government treasuries	117,131		—		—		117,131
U.S. government agency securities	—		1,977		—		1,977
Corporate debt securities	—		28,773		—		28,773
Foreign currency derivative contracts	—		14		—		14
Total	$	380,609	$	208,163	$	—	$	588,772
Liabilities:
Foreign currency derivative contracts	$	—	$	182	$	—	$	182
Total	$	—	$	182	$	—	$	182

The carrying amounts of prepaid expenses and other current assets, accounts payable and accrued liabilities approximate their fair values due to their short-term maturities.

The Company’s Level 2 securities are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly.

There were no transfers of assets or liabilities between the fair value measurement levels during the years ended December 31, 2019 or 2018.