Debt	9 Months Ended
Sep. 30, 2017
Debt
Debt	8. Debt Credit Line Agreement In September 2015, the Company entered into a credit line with UBS (the “Credit Line”) providing for a $50.0 million revolving line of credit that can be drawn down in increments at any time. In October 2015, the Company borrowed $32.0 million against the Credit Line, primarily to prepay all outstanding amounts under the Secured Loan Arrangement with ROS Acquisition Offshore, LP. The Credit Line bears interest at 30-day LIBOR plus 0.65%. The Credit Line is secured by a first priority lien and security interest in the Company’s money market and marketable securities held in its managed investment account with UBS. UBS has the right to demand full or partial payment of the Credit Line Obligations and terminate the Credit Line, in its discretion and without cause, at any time. In November 2015, the Company borrowed an additional $10.0 million from the Credit Line to provide working capital, which increased the total principal amount outstanding to $42.0 million. In June 2016, the Company borrowed an additional $8.0 million and repaid $1.0 million on the Credit Line, thereby increasing the total principal amount outstanding to $49.0 million, with accrued interest of $0.6 million as of December 31, 2016. For the nine months ended September 30, 2017, $0.7 million additional interest was accrued, and the Company has made interest payments of $0.2 million. As of September 30, 2017, interest accrued was $1.1 million, and the total principal amount outstanding with accrued interest was $50.1 million. 2017 Term Loan In August 2017, the Company entered into the 2017 Term Loan with OrbiMed, which has a maximum borrowing capacity of $100.0 million. On the closing date of August 8, 2017, the Company borrowed $75.0 million, with the remaining $25.0 million available to borrow at the Company’s option at any time through December 31, 2018, subject to standard conditions. The amounts borrowed under 2017 Term Loan will primarily be used for general corporate purposes and to fund and support the Company’s business and operations. Interest is accrued on the outstanding balance of the loan at a rate equal to the sum of (i) 8.75% plus (ii) the higher of 1.00% or LIBOR. The 2017 Term Loan has an eighty-four month term and will mature in August 2024. The Company is required to make interest payments on a quarterly basis, with repayment of the full outstanding balance on the maturity date. The Company’s obligations under the 2017 Term Loan are secured by substantially all of its assets, including its intellectual property, subject to certain customary exceptions. The 2017 Term Loan contains customary affirmative and negative covenants including financial information maintenance covenants, indebtedness limitation covenants, minimum net revenues covenants, and investment covenants. It also includes standard events of default such as payment defaults and nonperformance of obligations and covenants described above. Upon an event of default, an additional interest of 3.00% may be applied to the outstanding debt balance until such default is cured, and OrbiMed may declare all outstanding obligations immediately due and payable. As of September 30, 2017, the Company was in compliance with all of its covenants under the 2017 Term Loan. The Company is allowed to voluntarily make prepayments on its outstanding debt balance either partially or in full. When prepayments are made, an additional prepayment premium will be applied to the outstanding principal amount at the time. The prepayment premium will gradually reduce from 12.5% to 2.5% over the term of the loan. For the three months ended September 30, 2017, interest accrued on the 2017 Term Loan was $1.1 million, which was fully paid by the Company as of September 30, 2017. As of September 30, 2017, no principal repayment has been made as the Company is not required to repay the outstanding balance until August 2024. On August 14, 2017, the Company paid OrbiMed a fee in consideration of providing the 2017 Term Loan by issuing 300,000 shares of its common stock. The fair value of the fee was $2.4 million, which was determined based on the Company’s stock price of $8.16 on August 8, 2017 and is accounted for as a debt discount to be amortized on a straight-line basis over the term of the loan. The Company has classified $1.8 million of the debt discount as a direct reduction from the outstanding debt balance of $75.0 million, while the remainder is reported in noncurrent assets (as described in Note 5). For the three months ended September 30, 2017, the amount of the debt discount amortized as interest expense in the statements of operations and comprehensive loss was insignificant. As of September 30, 2017, the amount of the unamortized debt discount was $1.8 million, and the net carrying amount of the debt was $73.2 million.

8. Debt

Credit Line Agreement

In September 2015, the Company entered into a credit line with UBS (the “Credit Line”) providing for a $50.0 million revolving line of credit that can be drawn down in increments at any time. In October 2015, the Company borrowed $32.0 million against the Credit Line, primarily to prepay all outstanding amounts under the Secured Loan Arrangement with ROS Acquisition Offshore, LP. The Credit Line bears interest at 30-day LIBOR plus 0.65%. The Credit Line is secured by a first priority lien and security interest in the Company’s money market and marketable securities held in its managed investment account with UBS. UBS has the right to demand full or partial payment of the Credit Line Obligations and terminate the Credit Line, in its discretion and without cause, at any time.

In November 2015, the Company borrowed an additional $10.0 million from the Credit Line to provide working capital, which increased the total principal amount outstanding to $42.0 million. In June 2016, the Company borrowed an additional $8.0 million and repaid $1.0 million on the Credit Line, thereby increasing the total principal amount outstanding to $49.0 million, with accrued interest of $0.6 million as of December 31, 2016. For the nine months ended September 30, 2017, $0.7 million additional interest was accrued, and the Company has made interest payments of $0.2 million. As of September 30, 2017, interest accrued was $1.1 million, and the total principal amount outstanding with accrued interest was $50.1 million.

2017 Term Loan

In August 2017, the Company entered into the 2017 Term Loan with OrbiMed, which has a maximum borrowing capacity of $100.0 million. On the closing date of August 8, 2017, the Company borrowed $75.0 million, with the remaining $25.0 million available to borrow at the Company’s option at any time through December 31, 2018, subject to standard conditions. The amounts borrowed under 2017 Term Loan will primarily be used for general corporate purposes and to fund and support the Company’s business and operations. Interest is accrued on the outstanding balance of the loan at a rate equal to the sum of (i) 8.75% plus (ii) the higher of 1.00% or LIBOR. The 2017 Term Loan has an eighty-four month term and will mature in August 2024. The Company is required to make interest payments on a quarterly basis, with repayment of the full outstanding balance on the maturity date. The Company’s obligations under the 2017 Term Loan are secured by substantially all of its assets, including its intellectual property, subject to certain customary exceptions.

The 2017 Term Loan contains customary affirmative and negative covenants including financial information maintenance covenants, indebtedness limitation covenants, minimum net revenues covenants, and investment covenants. It also includes standard events of default such as payment defaults and nonperformance of obligations and covenants described above. Upon an event of default, an additional interest of 3.00% may be applied to the outstanding debt balance until such default is cured, and OrbiMed may declare all outstanding obligations immediately due and payable. As of September 30, 2017, the Company was in compliance with all of its covenants under the 2017 Term Loan.

The Company is allowed to voluntarily make prepayments on its outstanding debt balance either partially or in full. When prepayments are made, an additional prepayment premium will be applied to the outstanding principal amount at the time. The prepayment premium will gradually reduce from 12.5% to 2.5% over the term of the loan.

For the three months ended September 30, 2017, interest accrued on the 2017 Term Loan was $1.1 million, which was fully paid by the Company as of September 30, 2017. As of September 30, 2017, no principal repayment has been made as the Company is not required to repay the outstanding balance until August 2024.

On August 14, 2017, the Company paid OrbiMed a fee in consideration of providing the 2017 Term Loan by issuing 300,000 shares of its common stock. The fair value of the fee was $2.4 million, which was determined based on the Company’s stock price of $8.16 on August 8, 2017 and is accounted for as a debt discount to be amortized on a straight-line basis over the term of the loan. The Company has classified $1.8 million of the debt discount as a direct reduction from the outstanding debt balance of $75.0 million, while the remainder is reported in noncurrent assets (as described in Note 5). For the three months ended September 30, 2017, the amount of the debt discount amortized as interest expense in the statements of operations and comprehensive loss was insignificant. As of September 30, 2017, the amount of the unamortized debt discount was $1.8 million, and the net carrying amount of the debt was $73.2 million.