Summary of Significant Accounting Policies - Disaggregation of Revenue (Details)	12 Months Ended
Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue percentage by product group	100.00%	100.00%	100.00%
EDA
Disaggregation of Revenue [Line Items]
Revenue percentage by product group	59.00%	62.00%	66.00%
IP & System Integration
Disaggregation of Revenue [Line Items]
Revenue percentage by product group	31.00%	29.00%	28.00%
Software Integrity Products & Services
Disaggregation of Revenue [Line Items]
Revenue percentage by product group	10.00%	9.00%	6.00%
Other
Disaggregation of Revenue [Line Items]
Revenue percentage by product group	0.00%	0.00%	0.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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