| Cover | Jun. 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 10, 2022 |
| Entity File Number | 001-36020 |
| Entity Registrant Name | Onconova Therapeutics, Inc. |
| Entity Central Index Key | 0001130598 |
| Entity Tax Identification Number | 22-3627252 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 12 Penns Trail |
| Entity Address, City or Town | Newtown |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18940 |
| City Area Code | 267 |
| Local Phone Number | 759-3680 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $.01 per share |
| Trading Symbol | ONTX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
