Net Loss Per Share Net Loss Per Share Conversion Shares (Details) - Convertible Senior Notes - $ / shares shares in Millions	3 Months Ended
Apr. 30, 2020	Sep. 21, 2018
Potentially dilutive securities
Conversion spread of dilutive effect of convertible senior notes	14.3
Initial conversion price		$ 148.30

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No definition available.

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031898-161870

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 40
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-SubTopic 10
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