Accrued Expenses and Other Current Liabilities (Narrative) (Details)	6 Months Ended
Jan. 31, 2021
Payables and Accruals [Abstract]
Minimum coverage period of product warranty from the date of shipment	1 year

Minimum coverage period of product warranty from the date of shipment

No definition available.

Name:	cmtl_MinimumCoveragePeriodOfProductWarrantyFromDateOfShipment
Namespace Prefix:	cmtl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration