Notes Payable	3 Months Ended
Mar. 31, 2016
Debt Disclosure [Abstract]
Notes Payable	7. Notes Payable *Square 1 Bank Loan* In August 2014, the Company entered into a secured loan (the “Loan”) with Square 1 Bank, which loan is held by Pacific Western Bank as successor in interest by merger to Square 1 Bank) (the “Bank”). The Loan provides the Company with a term loan in the aggregate principal amount not to exceed $7.5 million to be used to supplement working capital. The Loan was available to the Company in four tranches: $1.5 million was made available to the Company on August 22, 2014 (“Tranche 1 Loan”), $1.5 million was made available to the Company upon enrollment of the first patient in its Phase 2 clinical trial for HS-110 on December 30, 2014 (“Tranche 2 Loan”), $2.25 million was made available to the Company upon the initiation of the Phase 1b trial for lung cancer indication on June 30, 2015 (“Tranche 3 Loan”), and $2.25 million was made available to the Company upon the Bank’s receipt of evidence on December 30, 2015 of the full enrollment of our Phase 1/2 clinical trial for HS-410 (“Tranche 4 Loan”). At December 31, 2015, the Company had drawn down the entire $7.5 million available under the Loan. The Loan accrues interest monthly at an interest rate of 3.05% plus the prime rate, or 6.30% per annum, whichever is greater. The Tranche 1 Loan was payable as interest-only until June 30, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 2 Loan was payable as interest-only prior to October 31, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 3 Loan was payable as interest-only prior to October 31, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 4 Loan is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Company has made $806,562 and $0 in principal payments for the quarter ended March 31, 2016 and 2015, respectively. The Company has made $110,377 and $50,393 in interest payments on the outstanding loan for the quarter ended March 31, 2016 and 2015, respectively. The agreement with the Bank sets forth various affirmative and negative covenants. The failure of the Company to comply with one or more of the covenants constitutes a default under the Loan. The covenants were amended in February 2016 to include the following: (i) the Company on or before September 30, 2016, having enrolled at least 18 patients in the Company’s DURGA (HS-110) clinical trial; (ii) the Company on or before December 31, 2016, having received favorable data readout from the Phase 2 randomized trial arms evaluating the Company’s HS-410 product; and (iii) after December 31, 2016, the Bank and the Company setting additional milestone covenants based upon a Board-approved plan of the Company sufficient to fund the operations necessary to achieve such milestones. The Loan also includes covenants regarding financial reporting, limits on the Company’s cash burn, incurrence of indebtedness, permitted investments, encumbrances, distributions, investments and mergers and acquisitions. The Loan is also secured by a security interest in all of the Company’s personal property, excluding its intellectual property. The Company is in compliance with the covenants of the Loan as of March 31, 2016.

Notes Payable

3 Months Ended

Mar. 31, 2016

7. Notes Payable

Square 1 Bank Loan

In August 2014, the Company entered into a secured loan (the “Loan”) with Square 1 Bank, which loan is held by Pacific Western Bank as successor in interest by merger to Square 1 Bank) (the “Bank”). The Loan provides the Company with a term loan in the aggregate principal amount not to exceed $7.5 million to be used to supplement working capital. The Loan was available to the Company in four tranches: $1.5 million was made available to the Company on August 22, 2014 (“Tranche 1 Loan”), $1.5 million was made available to the Company upon enrollment of the first patient in its Phase 2 clinical trial for HS-110 on December 30, 2014 (“Tranche 2 Loan”), $2.25 million was made available to the Company upon the initiation of the Phase 1b trial for lung cancer indication on June 30, 2015 (“Tranche 3 Loan”), and $2.25 million was made available to the Company upon the Bank’s receipt of evidence on December 30, 2015 of the full enrollment of our Phase 1/2 clinical trial for HS-410 (“Tranche 4 Loan”). At December 31, 2015, the Company had drawn down the entire $7.5 million available under the Loan.

The Loan accrues interest monthly at an interest rate of 3.05% plus the prime rate, or 6.30% per annum, whichever is greater. The Tranche 1 Loan was payable as interest-only until June 30, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 2 Loan was payable as interest-only prior to October 31, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 3 Loan was payable as interest-only prior to October 31, 2015 and thereafter is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Tranche 4 Loan is payable in monthly installments of principal plus accrued interest until February 22, 2018. The Company has made $806,562 and $0 in principal payments for the quarter ended March 31, 2016 and 2015, respectively. The Company has made $110,377 and $50,393 in interest payments on the outstanding loan for the quarter ended March 31, 2016 and 2015, respectively. The agreement with the Bank sets forth various affirmative and negative covenants. The failure of the Company to comply with one or more of the covenants constitutes a default under the Loan. The covenants were amended in February 2016 to include the following: (i) the Company on or before September 30, 2016, having enrolled at least 18 patients in the Company’s DURGA (HS-110) clinical trial; (ii) the Company on or before December 31, 2016, having received favorable data readout from the Phase 2 randomized trial arms evaluating the Company’s HS-410 product; and (iii) after December 31, 2016, the Bank and the Company setting additional milestone covenants based upon a Board-approved plan of the Company sufficient to fund the operations necessary to achieve such milestones. The Loan also includes covenants regarding financial reporting, limits on the Company’s cash burn, incurrence of indebtedness, permitted investments, encumbrances, distributions, investments and mergers and acquisitions. The Loan is also secured by a security interest in all of the Company’s personal property, excluding its intellectual property. The Company is in compliance with the covenants of the Loan as of March 31, 2016.