Represents the number of customers contributing to the net sales revenue of the entity.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

+ Details

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Period Type:	duration

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cmn_HealthcareDisposablesMember
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- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cmn_DialysisMember
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- Details

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- Details

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- Details

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Data Type:	na
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- Details

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- Details

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- Details

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Information as to Operating Segments and Foreign and Domestic Operations (Details)	3 Months Ended								12 Months Ended
	Jul. 31, 2015 USD ($)	Apr. 30, 2015 USD ($)	Jan. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Jul. 31, 2014 USD ($)	Apr. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	Oct. 31, 2013 USD ($)	Jul. 31, 2015 USD ($) item	Jul. 31, 2014 USD ($)	Jul. 31, 2013 USD ($)
Concentration risk
Consolidated net sales	$ 151,255,000	$ 141,508,000	$ 135,430,000	$ 136,811,000	$ 131,377,000	$ 120,058,000	$ 119,042,000	$ 118,272,000	$ 565,004,000	$ 488,749,000	$ 425,026,000
Water Purification and Filtration
Concentration risk
Consolidated net sales									173,834,000	159,505,000	134,196,000
Healthcare Disposables
Concentration risk
Consolidated net sales									106,920,000	101,809,000	90,904,000
Dialysis
Concentration risk
Consolidated net sales									$ 31,240,000	$ 30,926,000	$ 33,148,000
Segment sales \| Customer concentration \| Water Purification and Filtration \| Two customers
Concentration risk
Number of customers concentration risk \| item									2
Concentration risk (as a percent)									45.90%
Segment sales \| Customer concentration \| Healthcare Disposables \| Four customers
Concentration risk
Number of customers concentration risk \| item									4
Concentration risk (as a percent)									49.00%
Segment sales \| Customer concentration \| Dialysis \| Da Vita Inc
Concentration risk
Concentration risk (as a percent)									27.70%
Net sales \| Customer concentration \| Da Vita Inc
Concentration risk
Concentration risk (as a percent)										10.00%	10.40%
Consolidated net sales										$ 48,620,000	$ 44,204,000