Fair Value of Financial Instruments (Tables)

12 Months Ended

Jul. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Available-for-sale Securities Reconciliation

Available-for-sale investments within cash equivalents and investments consist of the following (in thousands):

	July 31, 2020
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Government agency securities	$	242,153	$	202	$	(81)	$	242,274
Commercial paper	222,578		—		—		222,578
Corporate bonds	474,646		3,448		(38)		478,056
U.S. Government bonds	68,332		476		—		68,808
Asset-backed securities	58,564		306		—		58,870
Certificates of deposit	56,296		—		—		56,296
Money market funds	231,063		—		—		231,063
Total	$	1,353,632	$	4,432	$	(119)	$	1,357,945

	July 31, 2019
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Government agency securities	$	55,904	$	4	$	(29)	$	55,879
Commercial paper	239,333		—		—		239,333
Corporate bonds	666,087		1,612		(111)		667,588
U.S. Government bonds	130,530		94		(29)		130,595
Certificates of deposit	50,796		—		—		50,796
Money market funds	115,711		—		—		115,711
Total	$	1,258,361	$	1,710	$	(169)	$	1,259,902

Schedule of Unrealized Loss on Investments

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses, aggregated by investment category and the length of time that individual securities have been in an unrealized loss position (in thousands):

	July 31, 2020
	Less Than 12 Months				12 Months or Greater				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Government agency securities	$	34,195	$	(81)	$	—	$	—	$	34,195	$	(81)
Corporate bonds	21,238		(38)		—		—		21,238		(38)
Total	$	55,433	$	(119)	$	—	$	—	$	55,433	$	(119)

Investments Classified by Contractual Maturity Date

The following table summarizes the contractual maturities of the Company’s available-for-sale investments measured at fair value (in thousands):

	July 31, 2020
	Less Than 12 Months		12 to 36 Months		Total
U.S. Government agency securities	$	110,089	$	132,185	$	242,274
Commercial paper	222,578		—		222,578
Corporate bonds	358,175		119,881		478,056
U.S. Government bonds	63,773		5,035		68,808
Asset-backed securities	25,448		33,422		58,870
Certificates of deposit	47,048		9,248		56,296
Money market funds	231,063		—		231,063
Total	$	1,058,174	$	299,771	$	1,357,945

Company's financial instruments measured at fair value on a recurring basis

The following tables summarize the Company’s available-for-sale investments measured at fair value, by level within the fair value hierarchy (in thousands):

	July 31, 2020
	Level 1		Level 2		Level 3		Total
Cash equivalents:
Commercial paper	$	—	$	60,584	$	—	$	60,584
Money market funds	231,063		—		—		231,063
Total cash equivalents	231,063		60,584		—		291,647
Short-term investments:
U.S. Government agency securities	—		110,089		—		110,089
Commercial paper	—		161,994		—		161,994
Corporate bonds	—		358,175		—		358,175
U.S. Government bonds	—		63,773		—		63,773
Asset-backed securities	—		25,448		—		25,448
Certificates of deposit	—		47,048		—		47,048
Total short-term investments	—		766,527		—		766,527
Long-term investments:
U.S. Government agency securities	—		132,185		—		132,185
Corporate bonds	—		119,881		—		119,881
U.S. Government bonds	—		5,035		—		5,035
Asset-backed securities	—		33,422		—		33,422
Certificates of deposit	—		9,248		—		9,248
Total long-term investments	—		299,771		—		299,771
Total	$	231,063	$	1,126,882	$	—	$	1,357,945

	July 31, 2019
	Level 1		Level 2		Level 3		Total
Cash and cash equivalents:
Commercial paper	$	—	$	56,132	$	—	$	56,132
Corporate bonds	—		4,398		—		4,398
Money market funds	115,712		—		—		115,712
Total cash equivalents	115,712		60,530		—		$	176,242
Short-term investments:
U.S. Government agency securities	—		39,166		—		39,166
Commercial paper	—		183,201		—		183,201
Corporate bonds	—		477,169		—		477,169
U. S. Government bonds	—		123,600		—		123,600
Certificates of deposit	—		47,000		—		47,000
Total short-term investments	—		870,136		—		870,136
Long-term investments:
U.S. Government agency securities	—		16,713		—		16,713
Corporate bonds	—		186,021		—		186,021
U.S. Government bonds	—		6,994		—		6,994
Certificates of deposit	—		3,796		—		3,796
Total long-term investments	—		213,524		—		213,524
Total	$	115,712	$	1,144,190	$	—	$	1,259,902