cm:Concept: us-gaap:ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock
| Proceeds from Issuance of Redeemable Convertible Preferred Stock |
| us-gaap:ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock |
| The cash inflow from issuance of callable preferred stock which is identified as being convertible to another type of financial security at the option of the issuer or the holder. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock |