Percentage of revenue generated from a single external customer type.

No definition available.

Name:	cmtl_EntityWideRevenuePercentageByMajorCustomerType
Namespace Prefix:	cmtl_
Data Type:	num:percentItemType
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Period Type:	duration

- Definition

The minimum percentage of consolidated net sales that, if made to one customer or country, would require additional and separate disclosure.

+ References

No definition available.

+ Details

Name:	cmtl_MinimumPercentageOfConsolidatedNetSalesToOneCustomerOrIndividualCountryRequiringAdditionalDisclosure
Namespace Prefix:	cmtl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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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Period Type:	duration

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
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- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
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Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_USGovernmentMember
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Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_CommercialMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_TotalUnitedStatesMember
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Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_NorthAfricanCountryMember
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Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_OtherInternationalMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_TotalInternationalSalesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	cmtl_RevenuePercentageByCustomerTypeAxis=cmtl_U.S.PrimeContractorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Customer and Geographic Information (Details) - USD ($)	3 Months Ended		9 Months Ended
Customer and Geographic Information (Details) - USD ($)	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Major customer
Revenues from External Customers
Minimum percentage of consolidated net sales sold to one customer or individual country requiring additional and separate disclosure	10.00%	10.00%	10.00%	10.00%
Major customer \| Sales Revenue, Net
Revenues from External Customers
Percentage of revenue generated from external customer type	0.00%		0.00%
U.S. government
Revenues from External Customers
Percentage of revenue generated from external customer type	41.90%	37.50%	41.80%	29.70%
Commercial (United States)
Revenues from External Customers
Percentage of revenue generated from external customer type	35.20%	11.90%	26.00%	12.50%
Total United States
Revenues from External Customers
Percentage of revenue generated from external customer type	77.10%	49.40%	67.80%	42.20%
North African country
Revenues from External Customers
Percentage of revenue generated from external customer type	0.90%	17.30%	2.60%	15.60%
Other international
Revenues from External Customers
Percentage of revenue generated from external customer type	22.00%	33.30%	29.60%	42.20%
Total International
Revenues from External Customers
Revenue generated from external customers	$ 28,417,000	$ 36,243,000	$ 83,401,000	$ 132,767,000
Percentage of revenue generated from external customer type	22.90%	50.60%	32.20%	57.80%
U.S. Prime Contractor \| Major customer \| Sales Revenue, Net
Revenues from External Customers
Percentage of revenue generated from external customer type		17.00%		15.20%