Summary of Significant Accounting Policies - Warranty (Details)	12 Months Ended
Mar. 31, 2022
Warranty
Warranty period	24 months

Represents the period of warranty service provided by the entity on its products and services.

No definition available.

Name:	cgrn_ProductWarrantyPeriod
Namespace Prefix:	cgrn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration