The number of equity instruments that the holder of the debt instrument would receive if the debt was converted to equity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentConvertibleNumberOfEquityInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Net Loss Per Share - Net Loss Per Share Conversion Shares (Details) shares in Millions		3 Months Ended
	Oct. 31, 2020 shares $ / shares	Oct. 31, 2020 $ / shares	Jun. 05, 2020 $ / shares	Sep. 21, 2018 $ / shares
Potentially dilutive securities
Average market price of common stock (in dollars per share)		$ 200.59
Convertible Senior Notes
Potentially dilutive securities
Number of shares potentially converted \| shares	16.0
Convertible Senior Notes \| 2023 Notes
Potentially dilutive securities
Initial conversion price (in dollars per share)	$ 148.30	148.30		$ 148.30
Convertible Senior Notes \| 2025 Notes
Potentially dilutive securities
Initial conversion price (in dollars per share)	148.30	148.30		$ 148.30
Convertible Senior Notes \| 2027 Notes
Potentially dilutive securities
Initial conversion price (in dollars per share)	$ 255.34	$ 255.34	$ 255.34