Related Party Transactions	6 Months Ended
Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	12. Related Party Transactions Board of Directors and Outside Counsel A member of the Company’s Board of Directors is a member of the Company’s outside counsel. During the three months ended June 30, 2017 and 2016, the Company incurred expenses of $139,000 and $249,000, respectively, related to services provided by the outside counsel. During the six months ended June 30, 2017 and 2016, the Company incurred expenses of $217,000 and $561,000, respectively, related to services provided by the outside counsel. On June 30, 2017 the Company’s outstanding payables and accrued expenses included a $65,000 liability to the outside counsel. Rights Offering-Backstop Agreement On October 13, 2016, in connection with the Rights Offering as discussed above, the Company entered into the Backstop Agreement with an affiliate of M&F and the other Backstop Parties. Under the terms of the Backstop Agreement, the Backstop Parties agreed to purchase, pursuant to a separate private placement, a number of shares of common stock equal to the numbers of shares that would have not been subscribed for in the Rights Offering. The Backstop Agreement provided that the subscription price for the Backstop Parties would be equal to the subscription price applicable to all shareholders under the Rights Offering. Because the Rights Offering was fully subscribed, the Backstop Parties were not required to draw on such commitment. The Company issued 708,530 shares to Backstop Parties, of which approximately 565,000 shares were received by M&F, in payment of the five percent backstop fee ($1,764,240) payable to the Backstop Parties in connection with the backstop agreement. When shares were issued to the Backstop Parties in payment of the backstop fee, the stock price of SIGA common stock was $2.49 per share (the closing price of the Company’s common stock on November 16, 2016). The fair value of the shares issued in satisfaction of the backstop fee was expensed to the income statement in 2016. There are no remaining payment obligations to the Backstop Parties under the Backstop Agreement. Real Estate Leases On May 26, 2017 the Company and MacAndrews & Forbes Incorporated entered into a ten-year Office Lease agreement (the “New HQ Lease”), pursuant to which the Company agreed to lease 3,200 square feet at 27 East 62^nd Street, New York, New York. The Company is utilizing premises leased under the New HQ Lease as its new corporate headquarters. The Company's rental obligations consist of a fixed rent of $25,333, per month in the first sixty-three months of the term, subject to a rent abatement for the first six months of the term. From the first day of the sixty-fourth month of the term through the expiration or earlier termination of the lease, the Company's rental obligations consist of a fixed rent of $29,333 per month. In addition to the fixed rent, the Company will pay a facility fee in consideration of the landlord making available certain ancillary services, commencing on the first anniversary of entry into the lease. The facility fee will be $3,333 per month for the second year of the term and increasing by five percent each year thereafter, to $4,925 per month in the final year of the term. On July 31, 2017, the Company and M&F, entered into a Termination of Sublease Agreement (the “Old HQ Sublease Termination Agreement”), pursuant to which the Company and M&F have agreed to terminate the sublease dated January 9, 2013 for 6,676 square feet of rental square footage located at 660 Madison Avenue, Suite 1700, New York, New York (such sublease being the “Old HQ Sublease” and the location being the “Old HQ”). Effectiveness of the Old HQ Sublease Termination Agreement was conditioned upon the commencement of a sublease for the Old HQ between M&F and a new subtenant (the “Replacement M&F Sublease”), which occurred on August 2, 2017. The Old HQ Sublease Termination Agreement obligates the Company to pay, on a monthly basis, an amount equal to the discrepancy (the “Rent Discrepancy”) between the sum of fixed rent and Additional Rent (as defined below) under the Old HQ Overlease (as defined below) and the sum of fixed rent and Additional Rent under the Replacement M&F Sublease. Under the Old HQ Sublease Termination Agreement, the Company and M&F release each other from any liability under the Old HQ Sublease. Under the Old HQ Sublease, the Company was obligated to pay fixed rent of approximately $60,000 per month until August 2018 and approximately $63,400 per month thereafter until the Old HQ Sublease expiration date of August 31, 2020. Additionally, the Company was obligated to pay certain operating expenses and taxes (“Additional Rent”), such Additional Rent being specified in the overlease between M&F and the landlord at 660 Madison Avenue (the “Old HQ Overlease”). Under the Replacement M&F Sublease, the subtenant’s rental obligations are excused for the first two (2) months of the lease term (“Rent Concession Period”). Thereafter, the subtenant is obligated to pay fixed rent of $36,996 per month for the first twelve (12) months, $37,831 per month for the next 12 months, and $38,665 per month until the scheduled expiration of the Replacement M&F Sublease on August 24, 2020. In addition to fixed rent, the subtenant is also obligated to pay, pursuant to the Replacement M&F Sublease, a portion of the Additional Rent specified in the Old HQ Overlease. For the time period between August 2, 2017 and August 31, 2020 (the expiration date of the Old HQ Sublease), the Company estimates that it will pay a total of approximately $0.9 million combined in fixed rent and additional amounts payable under the New HQ Lease and a total of approximately $1.1 million in Rent Discrepancy under the Old HQ Sublease Termination Agreement, for a cumulative total of $2.0 million. In contrast, fixed rent and estimated Additional Rent under the Old HQ Sublease, for the aforementioned time period, would have been a total of approximately $2.4 million if each of the New HQ Lease, Replacement M&F Sublease and Old HQ Sublease Termination Agreement had not been entered into by each of the parties thereto. Because amounts such as operating expenses and taxes may vary, the foregoing totals can only be estimated at this time and are subject to change. As a result of the above-mentioned transactions, the Company has discontinued usage of Old HQ in the third quarter. As such, the Company expects to record a liability in the third quarter of 2017 in the approximate range of $1.0 million to $1.2 million, in accordance with Accounting Standards Codification (“ASC”) 420 Exit or Disposal Obligations. The liability will primarily represent the discounted value of estimated Rent Discrepancy payments to occur in the future, and will also include costs related to the termination of the old HQ Sublease. The Company also expects to write-off approximately $0.1 million of leasehold improvements and furniture related to the Old HQ.

12. Related Party Transactions

Board of Directors and Outside Counsel

A member of the Company’s Board of Directors is a member of the Company’s outside counsel. During the three months ended June 30, 2017 and 2016, the Company incurred expenses of $139,000 and $249,000, respectively, related to services provided by the outside counsel. During the six months ended June 30, 2017 and 2016, the Company incurred expenses of $217,000 and $561,000, respectively, related to services provided by the outside counsel. On June 30, 2017 the Company’s outstanding payables and accrued expenses included a $65,000 liability to the outside counsel.

Rights Offering-Backstop Agreement

On October 13, 2016, in connection with the Rights Offering as discussed above, the Company entered into the Backstop Agreement with an affiliate of M&F and the other Backstop Parties. Under the terms of the Backstop Agreement, the Backstop Parties agreed to purchase, pursuant to a separate private placement, a number of shares of common stock equal to the numbers of shares that would have not been subscribed for in the Rights Offering. The Backstop Agreement provided that the subscription price for the Backstop Parties would be equal to the subscription price applicable to all shareholders under the Rights Offering. Because the Rights Offering was fully subscribed, the Backstop Parties were not required to draw on such commitment. The Company issued 708,530 shares to Backstop Parties, of which approximately 565,000 shares were received by M&F, in payment of the five percent backstop fee ($1,764,240) payable to the Backstop Parties in connection with the backstop agreement. When shares were issued to the Backstop Parties in payment of the backstop fee, the stock price of SIGA common stock was $2.49 per share (the closing price of the Company’s common stock on November 16, 2016). The fair value of the shares issued in satisfaction of the backstop fee was expensed to the income statement in 2016. There are no remaining payment obligations to the Backstop Parties under the Backstop Agreement.

Real Estate Leases

On May 26, 2017 the Company and MacAndrews & Forbes Incorporated entered into a ten-year Office Lease agreement (the “New HQ Lease”), pursuant to which the Company agreed to lease 3,200 square feet at 27 East 62^nd Street, New York, New York. The Company is utilizing premises leased under the New HQ Lease as its new corporate headquarters. The Company's rental obligations consist of a fixed rent of $25,333, per month in the first sixty-three months of the term, subject to a rent abatement for the first six months of the term. From the first day of the sixty-fourth month of the term through the expiration or earlier termination of the lease, the Company's rental obligations consist of a fixed rent of $29,333 per month. In addition to the fixed rent, the Company will pay a facility fee in consideration of the landlord making available certain ancillary services, commencing on the first anniversary of entry into the lease. The facility fee will be $3,333 per month for the second year of the term and increasing by five percent each year thereafter, to $4,925 per month in the final year of the term.

On July 31, 2017, the Company and M&F, entered into a Termination of Sublease Agreement (the “Old HQ Sublease Termination Agreement”), pursuant to which the Company and M&F have agreed to terminate the sublease dated January 9, 2013 for 6,676 square feet of rental square footage located at 660 Madison Avenue, Suite 1700, New York, New York (such sublease being the “Old HQ Sublease” and the location being the “Old HQ”).

Effectiveness of the Old HQ Sublease Termination Agreement was conditioned upon the commencement of a sublease for the Old HQ between M&F and a new subtenant (the “Replacement M&F Sublease”), which occurred on August 2, 2017. The Old HQ Sublease Termination Agreement obligates the Company to pay, on a monthly basis, an amount equal to the discrepancy (the “Rent Discrepancy”) between the sum of fixed rent and Additional Rent (as defined below) under the Old HQ Overlease (as defined below) and the sum of fixed rent and Additional Rent under the Replacement M&F Sublease. Under the Old HQ Sublease Termination Agreement, the Company and M&F release each other from any liability under the Old HQ Sublease.

Under the Old HQ Sublease, the Company was obligated to pay fixed rent of approximately $60,000 per month until August 2018 and approximately $63,400 per month thereafter until the Old HQ Sublease expiration date of August 31, 2020. Additionally, the Company was obligated to pay certain operating expenses and taxes (“Additional Rent”), such Additional Rent being specified in the overlease between M&F and the landlord at 660 Madison Avenue (the “Old HQ Overlease”).

Under the Replacement M&F Sublease, the subtenant’s rental obligations are excused for the first two (2) months of the lease term (“Rent Concession Period”). Thereafter, the subtenant is obligated to pay fixed rent of $36,996 per month for the first twelve (12) months, $37,831 per month for the next 12 months, and $38,665 per month until the scheduled expiration of the Replacement M&F Sublease on August 24, 2020. In addition to fixed rent, the subtenant is also obligated to pay, pursuant to the Replacement M&F Sublease, a portion of the Additional Rent specified in the Old HQ Overlease.

For the time period between August 2, 2017 and August 31, 2020 (the expiration date of the Old HQ Sublease), the Company estimates that it will pay a total of approximately $0.9 million combined in fixed rent and additional amounts payable under the New HQ Lease and a total of approximately $1.1 million in Rent Discrepancy under the Old HQ Sublease Termination Agreement, for a cumulative total of $2.0 million. In contrast, fixed rent and estimated Additional Rent under the Old HQ Sublease, for the aforementioned time period, would have been a total of approximately $2.4 million if each of the New HQ Lease, Replacement M&F Sublease and Old HQ Sublease Termination Agreement had not been entered into by each of the parties thereto. Because amounts such as operating expenses and taxes may vary, the foregoing totals can only be estimated at this time and are subject to change.

As a result of the above-mentioned transactions, the Company has discontinued usage of Old HQ in the third quarter. As such, the Company expects to record a liability in the third quarter of 2017 in the approximate range of $1.0 million to $1.2 million, in accordance with Accounting Standards Codification (“ASC”) 420 Exit or Disposal Obligations. The liability will primarily represent the discounted value of estimated Rent Discrepancy payments to occur in the future, and will also include costs related to the termination of the old HQ Sublease. The Company also expects to write-off approximately $0.1 million of leasehold improvements and furniture related to the Old HQ.