Reportable Segments - Concentration Risk (Details) - Segment sales - Customer concentration	3 Months Ended
Oct. 31, 2019	Oct. 31, 2018
Life Sciences \| Two customers
Concentration risk
Concentration risk within segment (as a percent)	45.70%	43.90%
Dental \| Three customers
Concentration risk
Concentration risk within segment (as a percent)	43.50%	50.20%
Dialysis \| Three customers
Concentration risk
Concentration risk within segment (as a percent)	46.10%	41.40%

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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