| Document And Entity Information | Dec. 16, 2021 |
| Document Information [Line Items] | |
| Entity, Registrant Name | THERMOGENESIS HOLDINGS, INC. |
| Document, Type | 8-K |
| Document, Period End Date | Dec. 16, 2021 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 333-82900 |
| Entity, Tax Identification Number | 94-3018487 |
| Entity, Address, Address Line One | 2711 Citrus Rd. |
| Entity, Address, City or Town | Rancho Cordova |
| Entity, Address, State or Province | CA |
| Entity, Address, Postal Zip Code | 95742 |
| City Area Code | 916 |
| Local Phone Number | 858-5100 |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | THMO |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0000811212 |
