Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value Measurements

Schedule of assets measured at fair value on a recurring basis

	Fair Value Measurements as of June 30, 2020
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	452,247	$	452,247	$	—	$	—
Marketable securities
Bonds and bond funds	$	137,183	$	—	$	137,183	$	—
Commercial paper		172,640		—		172,640		—
		309,823		—		309,823		—
Total assets measured at fair value	$	762,070	$	452,247	$	309,823	$	—

	Fair Value Measurements as of December 31, 2019
	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	87,206	$	87,206	$	—	$	—
Marketable securities
Bonds and bond funds	$	267,243	$	—	$	267,243	$	—
Commercial paper		165,723		—		165,723		—
		432,966		—		432,966		—
Total assets measured at fair value	$	520,172	$	87,206	$	432,966	$	—