| Document and Entity Information | Mar. 31, 2021 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | SEACHANGE INTERNATIONAL INC |
| Amendment Flag | false |
| Entity Central Index Key | 0001019671 |
| Document Type | 8-K |
| Document Period End Date | Mar. 31, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38828 |
| Entity Tax Identification Number | 04-3197974 |
| Entity Address, Address Line One | 500 Totten Pond Road |
| Entity Address, City or Town | Waltham |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02451 |
| City Area Code | (978) |
| Local Phone Number | 897-0100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $0.01 Par Value |
| Trading Symbol | SEAC |
| Security Exchange Name | NASDAQ |
| Series A Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Series A Participating Preferred Stock Purchase Rights |
| Trading Symbol | SEAC |
| Security Exchange Name | NASDAQ |
