| Document and Entity Information | May 06, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 6, 2021 |
| Entity Registrant Name | SIGA TECHNOLOGIES, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-23047 |
| Entity Tax Identification Number | 13-3864870 |
| Entity Address, Address Line One | 31 EAST 62ND STREET |
| Entity Address, City or Town | NEW YORK |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10065 |
| City Area Code | 212 |
| Local Phone Number | 672-9100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001010086 |
| Title of 12(b) Security | common stock, $.0001 par value |
| Trading Symbol | SIGA |
| Security Exchange Name | NASDAQ |
