Long-term Debt	6 Months Ended
Jun. 30, 2016
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt On May 8, 2013, we entered into a loan and security agreement with Oxford Finance LLC, as collateral agent, and related lenders under which we borrowed the first tranche of $10 million (the "Loan"). The Loan payment terms include 12 months of interest-only payments at the fixed coupon rate of 8.45%, followed by 30 months of amortization of principal and interest until maturity in November 2016. In connection with the Loan, we paid the lender a 1% cash facility fee and a 5.5% cash final payment and granted to the lenders seven-year warrants to purchase up to 182,186 shares of our common stock at an exercise price of $2.47, which equaled a 20-day average market price of our common stock prior to the date of the grant. On May 10, 2016, the Company prepaid the outstanding principal amount and cash final payment. On May 10, 2016, the Company entered into a Securities Purchase Agreement, with certain purchasers pursuant to which the Company sold, at a 6.375% original issue discount, a total of $25,530,000 Senior Secured Debentures (the “Debentures”) and warrants to purchase up to 2.0 million shares of the Company's common stock. Net proceeds to the Company from sale of the Debentures, after payment of commissions and legal fees, were approximately $23,400,000. The Debentures mature November 10, 2018, accrue interest at 9% per year, and do not contain any conversion features into shares of our common stock. The Company intends to use the net proceeds from this offering to fund the costs associated with the close down of the Phase 3 PRESENT study of NeuVax and other clinical trials of our product candidates and to augment its working capital and for general corporate purposes. The Debentures carry an interest only period of six months following which the holder shall have the rights, at its option, to require the Company to redeem up to $1,100,000 per month of the outstanding principal amount of these Debentures. Interest is payable at the end of each month based on the outstanding principal. The Company is required to promptly, but in any event no more than three trading days after the holder delivers a redemption notice to the Company, pay the applicable redemption amount in cash or, at the Company’s election and subject to certain conditions, in shares of the Company's common stock. If the Company elects to pay the redemption amount in shares of its common stock, then the shares will be delivered at the lesser of A) 7.5% discount to the average of the 3 lowest volume weighted average prices over the prior 20 trading days or B) a 7.5% discount to the prior trading day’s volume weighted average price. The Company may only opt for payment in shares of common stock if certain equity conditions are met. The Company, at its option, may also force the holder to redeem up to double the monthly redemption principal amount of the Debentures but not less than the monthly payment. Based on the recommendation of the IDMC to stop the PRESENT Trial, the holder has the right to require the Company to prepay in cash all, or any portion, of the outstanding principal amount of this Debenture funded in cash by the holder on the closing date, plus all accrued and unpaid interest. If the holder elects such prepayment of the Debentures, then the number of shares subject to the warrants issued to the holder will be reduced in proportion to the percentage of principal required and accrued interest to be prepaid by the Company. The Purchaser received 1 million warrants upon the closing on the sale of the Debentures at an exercise price of $1.51, maturing 5 years from issuance. Additionally, the Purchasers received 1 million warrants upon the Company's public company announcement of the interim analysis on June 29, 2016 at an exercise price of $0.43. As of June 30, 2016 and the date of this filing, the holder had not exercised its right to require the Company to prepay in cash all, or any portion, of the outstanding principal amount of the Debentures. The holder's right to require the Company to prepay the outstanding principal amount expires 30 trading days after June 29, 2016, the announcement date of the recommendation of the IDMC. Therefore as of June 30, 2016 the Debentures, net of unamortized discounts, are presented as current liabilities on the condensed consolidated balance sheet. The Company’s obligations under the Debenture can be accelerated in the event the Company undergoes a change in control and other customary events of default. In the event of default and acceleration of the Company’s obligations, the Company would be required to pay all amounts of principal and interest then outstanding under the Debenture in cash. The Company’s obligations under the Debentures are secured under a Security Agreement by a senior lien on all of the Company’s assets, including all of the Company’s interests in its consolidated subsidiaries. Until the holder exercises its right to require the Company to prepay some or all of the loan, the Company must also maintain a minimum of $24.0 million in cash, which is included in restricted cash as of June 30, 2016. Armentum Partners, LLC (the “Placement Agent”) acted as the placement agent in the offering of the Debentures and the Company agreed to pay the Placement Agent a fee equal to 2% of the funds received from the sale of the Debentures. The Company paid half of the placement fee upon funding with the remaining payable at such time as the IDMC recommended in favor of the continuation of the PRESENT Trial or the holder waives the Company’s obligation to prepay the Debenture as a result of the IDMC’s recommendation.

Long-term Debt

On May 8, 2013, we entered into a loan and security agreement with Oxford Finance LLC, as collateral agent, and related lenders under which we borrowed the first tranche of $10 million (the "Loan"). The Loan payment terms include 12 months of interest-only payments at the fixed coupon rate of 8.45%, followed by 30 months of amortization of principal and interest until maturity in November 2016. In connection with the Loan, we paid the lender a 1% cash facility fee and a 5.5% cash final payment and granted to the lenders seven-year warrants to purchase up to 182,186 shares of our common stock at an exercise price of $2.47, which equaled a 20-day average market price of our common stock prior to the date of the grant. On May 10, 2016, the Company prepaid the outstanding principal amount and cash final payment.

On May 10, 2016, the Company entered into a Securities Purchase Agreement, with certain purchasers pursuant to which the Company sold, at a 6.375% original issue discount, a total of $25,530,000 Senior Secured Debentures (the “Debentures”) and warrants to purchase up to 2.0 million shares of the Company's common stock. Net proceeds to the Company from sale of the Debentures, after payment of commissions and legal fees, were approximately $23,400,000. The Debentures mature November 10, 2018, accrue interest at 9% per year, and do not contain any conversion features into shares of our common stock. The Company intends to use the net proceeds from this offering to fund the costs associated with the close down of the Phase 3 PRESENT study of NeuVax and other clinical trials of our product candidates and to augment its working capital and for general corporate purposes.

The Debentures carry an interest only period of six months following which the holder shall have the rights, at its option, to require the Company to redeem up to $1,100,000 per month of the outstanding principal amount of these Debentures. Interest is payable at the end of each month based on the outstanding principal.

The Company is required to promptly, but in any event no more than three trading days after the holder delivers a redemption notice to the Company, pay the applicable redemption amount in cash or, at the Company’s election and subject to certain conditions, in shares of the Company's common stock. If the Company elects to pay the redemption amount in shares of its common stock, then the shares will be delivered at the lesser of A) 7.5% discount to the average of the 3 lowest volume weighted average prices over the prior 20 trading days or B) a 7.5% discount to the prior trading day’s volume weighted average price. The Company may only opt for payment in shares of common stock if certain equity conditions are met. The Company, at its option, may also force the holder to redeem up to double the monthly redemption principal amount of the Debentures but not less than the monthly payment.

Based on the recommendation of the IDMC to stop the PRESENT Trial, the holder has the right to require the Company to prepay in cash all, or any portion, of the outstanding principal amount of this Debenture funded in cash by the holder on the closing date, plus all accrued and unpaid interest. If the holder elects such prepayment of the Debentures, then the number of shares subject to the warrants issued to the holder will be reduced in proportion to the percentage of principal required and accrued interest to be prepaid by the Company. The Purchaser received 1 million warrants upon the closing on the sale of the Debentures at an exercise price of $1.51, maturing 5 years from issuance. Additionally, the Purchasers received 1 million warrants upon the Company's public company announcement of the interim analysis on June 29, 2016 at an exercise price of $0.43. As of June 30, 2016 and the date of this filing, the holder had not exercised its right to require the Company to prepay in cash all, or any portion, of the outstanding principal amount of the Debentures. The holder's right to require the Company to prepay the outstanding principal amount expires 30 trading days after June 29, 2016, the announcement date of the recommendation of the IDMC. Therefore as of June 30, 2016 the Debentures, net of unamortized discounts, are presented as current liabilities on the condensed consolidated balance sheet.

The Company’s obligations under the Debenture can be accelerated in the event the Company undergoes a change in control and other customary events of default. In the event of default and acceleration of the Company’s obligations, the Company would be required to pay all amounts of principal and interest then outstanding under the Debenture in cash. The Company’s obligations under the Debentures are secured under a Security Agreement by a senior lien on all of the Company’s assets, including all of the Company’s interests in its consolidated subsidiaries. Until the holder exercises its right to require the Company to prepay some or all of the loan, the Company must also maintain a minimum of $24.0 million in cash, which is included in restricted cash as of June 30, 2016.

Armentum Partners, LLC (the “Placement Agent”) acted as the placement agent in the offering of the Debentures and the Company agreed to pay the Placement Agent a fee equal to 2% of the funds received from the sale of the Debentures. The Company paid half of the placement fee upon funding with the remaining payable at such time as the IDMC recommended in favor of the continuation of the PRESENT Trial or the holder waives the Company’s obligation to prepay the Debenture as a result of the IDMC’s recommendation.