Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table presents our fair value hierarchy for our assets measured at fair value on a recurring basis as of December 31, 2018 (in thousands):



	Level 1		Level 2		Total
Cash equivalents:
Money market funds	$	229,047	$	—	$	229,047
Commercial paper	—		16,961		16,961
Certificates of deposit	—		2,465		2,465
Short-term investments:
Commercial paper	—		108,061		108,061
Corporate notes and bonds	—		679,542		679,542
Certificates of deposit	—		56,596		56,596
U.S. government and agency securities	—		87,519		87,519
Long-term investments:
Corporate notes and bonds	—		550,172		550,172
Certificates of deposit	—		16,989		16,989
U.S. government and agency securities	—		14,695		14,695
Total	$	229,047	$	1,533,000	$	1,762,047

The following table presents our fair value hierarchy for our assets measured at fair value on a recurring basis as of December 31, 2017 (in thousands):



	Level 1		Level 2		Total
Cash equivalents:
Money market funds	$	282,507	$	—	$	282,507
Commercial paper	—		100,456		100,456
Corporate notes and bonds	—		50,437		50,437
Short-term investments:
Commercial paper	—		258,344		258,344
Corporate notes and bonds	—		688,316		688,316
Certificates of deposit	—		17,950		17,950
U.S. government and agency securities	—		67,476		67,476
Marketable equity securities	20,717		—		20,717
Long-term investments:
Corporate notes and bonds	—		314,928		314,928
Certificates of deposit	—		15,134		15,134
U.S. government and agency securities	—		61,380		61,380
Total	$	303,224	$	1,574,421	$	1,877,645