Debt	9 Months Ended
Sep. 30, 2019
Debt
Debt	10. 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. The Credit Line bears interest at 30-day LIBOR plus 1.10%. 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. For the three months ended September 30, 2019 and 2018, the Company recorded interest expense on the Credit Line of $0.4 million for both periods; and for the nine months ended September 30, 2019 and 2018, interest expense on the Credit Line of $1.3 million and $1.1 million was recorded, respectively. Interest payments on the Credit Line were made within the same periods. As of September 30, 2019, remaining accrued interest 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 have and will continue to 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. On December 31, 2018, the Company amended certain terms in the 2017 Term Loan with OrbiMed. The amendment increased the existing unused borrowing capacity from $25.0 million to $50.0 million and extended the expiration date for the option to draw the unused capacity to March 31, 2019. If such option were exercised by the Company, the interest rate described above would instead decrease to the sum of (i) 8.50% plus (ii) the higher of 1.00% or LIBOR. In April 2019, the Company entered into a second amendment on the 2017 Term Loan with OrbiMed to further extend the expiration date until December 31, 2019 to draw the unused borrowing capacity of $50.0 million. The second amendment reduces the interest rate to the sum of (i) 8.25% plus (ii) the higher of 1.00% or LIBOR from previously the sum of (i) 8.50% plus (ii) the higher of 1.00% of LIBOR, provided that a minimum capacity of $25.0 million were drawn. As a fee in consideration of extending the commitment to provide this option to draw until December 31, 2019, the Company issued an additional 25,000 shares of its common stock to OrbiMed as of April 29, 2019. As of September 30, 2019, the Company had not exercised such option. 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, 2019, 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. Initially, the Company paid OrbiMed a fee in consideration of providing the 2017 Term Loan by issuing 300,000 shares of its common stock at a fair value of $2.7 million. Following the second amendment on the term loan as described above, an additional 25,000 shares were issued to OrbiMed on April 29, 2019 at a fair value of $0.5 million. The fair value for total fees paid to date was $3.2 million, which is accounted for as a debt discount to be amortized on a straight-line basis over the remaining term of the loan. The Company has classified the cumulative debt discount of $2.0 million as a direct reduction from the outstanding debt balance of $75.0 million, while the remaining $1.2 million is classified as noncurrent assets (as described in Note 6). For the three months ended September 30, 2019 and 2018, the Company recorded interest expense for the 2017 Term Loan totaling $2.1 million for each period, and $6.5 million and $6.1 million for the nine months ended September 30, 2019 and 2018, respectively, which also included the amortization of debt discount. Debt discount amortized as interest expense in the statements of operations and comprehensive loss for the three months ended September 30, 2019 and 2018 was $0.1 million in each of the two periods, and $0.3 million in each of the nine month period ended September 30, 2019 and 2018. In addition, the Company made interest payments totaling $6.5 million and $6.1 million during the nine months ended September 30, 2019 and 2018, respectively. As of September 30, 2019, the amount of the unamortized debt discount was $1.4 million, and the net carrying amount of the debt was $73.6 million.

10. 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. The Credit Line bears interest at 30-day LIBOR plus 1.10%. 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.

For the three months ended September 30, 2019 and 2018, the Company recorded interest expense on the Credit Line of $0.4 million for both periods; and for the nine months ended September 30, 2019 and 2018, interest expense on the Credit Line of $1.3 million and $1.1 million was recorded, respectively. Interest payments on the Credit Line were made within the same periods. As of September 30, 2019, remaining accrued interest 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 have and will continue to 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.

On December 31, 2018, the Company amended certain terms in the 2017 Term Loan with OrbiMed. The amendment increased the existing unused borrowing capacity from $25.0 million to $50.0 million and extended the expiration date for the option to draw the unused capacity to March 31, 2019. If such option were exercised by the Company, the interest rate described above would instead decrease to the sum of (i) 8.50% plus (ii) the higher of 1.00% or LIBOR.

In April 2019, the Company entered into a second amendment on the 2017 Term Loan with OrbiMed to further extend the expiration date until December 31, 2019 to draw the unused borrowing capacity of $50.0 million. The second amendment reduces the interest rate to the sum of (i) 8.25% plus (ii) the higher of 1.00% or LIBOR from previously the sum of (i) 8.50% plus (ii) the higher of 1.00% of LIBOR, provided that a minimum capacity of $25.0 million were drawn. As a fee in consideration of extending the commitment to provide this option to draw until December 31, 2019, the Company issued an additional 25,000 shares of its common stock to OrbiMed as of April 29, 2019. As of September 30, 2019, the Company had not exercised such option.

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, 2019, 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.

Initially, the Company paid OrbiMed a fee in consideration of providing the 2017 Term Loan by issuing 300,000 shares of its common stock at a fair value of $2.7 million. Following the second amendment on the term loan as described above, an additional 25,000 shares were issued to OrbiMed on April 29, 2019 at a fair value of $0.5 million. The fair value for total fees paid to date was $3.2 million, which is accounted for as a debt discount to be amortized on a straight-line basis over the remaining term of the loan. The Company has classified the cumulative debt discount of $2.0 million as a direct reduction from the outstanding debt balance of $75.0 million, while the remaining $1.2 million is classified as noncurrent assets (as described in Note 6).

For the three months ended September 30, 2019 and 2018, the Company recorded interest expense for the 2017 Term Loan totaling $2.1 million for each period, and $6.5 million and $6.1 million for the nine months ended September 30, 2019 and 2018, respectively, which also included the amortization of debt discount. Debt discount amortized as interest expense in the statements of operations and comprehensive loss for the three months ended September 30, 2019 and 2018 was $0.1 million in each of the two periods, and $0.3 million in each of the nine month period ended September 30, 2019 and 2018. In addition, the Company made interest payments totaling $6.5 million and $6.1 million during the nine months ended September 30, 2019 and 2018, respectively. As of September 30, 2019, the amount of the unamortized debt discount was $1.4 million, and the net carrying amount of the debt was $73.6 million.