Loan and Security Agreement	12 Months Ended
Dec. 31, 2019
Debt Disclosure [Abstract]
Loan and Security Agreement	7. Loan and Security Agreement In August 2017, the Company entered into a loan and security agreement with Oxford and SVB under which it borrowed $15.0 million (the “August 2017 Loan”). The loan is due in 30 monthly installments from March 2019 through its repayment in August 2021, with interest-only monthly payments until March 2019. The Company commenced repayment of the loan in March 2019. The August 2017 Loan is secured by all assets of the Company, excluding intellectual property and certain other assets. The August 2017 Loan contains customary affirmative and restrictive covenants, including with respect to fundamental transactions, the incurrence of additional indebtedness, grant liens, pay any dividend or make any distributions to the Company’s holders, make investments, merge or consolidate with any other person, or engage in transactions with its affiliates, but does not include any financial covenants. The loan agreement provides that an event of default will occur if, among other triggers, there occurs any circumstances that could reasonably be expected to result in a material adverse effect on the Company’s business, operations or condition, or on its ability to perform its obligations under the loan. The loan agreement also includes customary representations and warranties, other events of default and termination provisions. The interest charges on the loan are based on a floating rate that equals the greater of 7.39% or the sum of the 30-day U.S. Dollar London Interbank Offered Rate (“LIBOR”) plus 6.40%. For the year ended December 31, 2019, the average interest rate was 8.72%. In addition, the Company will make a final payment equal to 3.83% of the original principal amount of the loan, or $0.6 million, which will be accrued over the term of the loan using the effective-interest method. As of December 31, 2019, total interest expense accrued was $0.4 million. In connection with the August 2017 Loan, the Company issued to Oxford and SVB a warrant to purchase the Company’s Series D-2 redeemable convertible preferred stock (the “2017 Warrant”). The 2017 Warrants were later converted into warrants to purchase Series E redeemable convertible preferred stock in May and July 2018, and upon the Company’s IPO on October 1, 2018, all Series E redeemable convertible preferred stock warrants were converted to warrants to purchase 46,359 shares of common stock. The estimated fair value upon issuance of the 2017 Warrant of $0.3 million was recorded as a debt discount on the associated borrowings on the Company’s balance sheet. The debt discount is being amortized to interest expense over the repayment period of the loan using the effective-interest method. During the years ended December 31, 2019, 2018 and 2017, the Company recorded interest expense related to this loan of $1.1 million, $1.6 million and $0.6 million, respectively. During the years ended December 31, 2019, 2018 and 2017, the Company recorded accretion of debt discount of $0.2 million, $0.2 million and $0.1 million, respectively. As described in Notes 1 and 15 of these financial statements, the Company entered into a Loan and Security Agreement on February 28, 2020, for gross proceeds of $25 million. Pursuant to the Loan and Security Agreement, $9.6 million of the gross proceeds were used to fully repay the August 2017 Loan. As a result, of the $9.9 million that was outstanding as of December 31, 2019, $8.9 million has been classified on our balance sheet as Debt – non-current. The remaining $1.0 million that was outstanding as of December 31, 2019 has been classified as Debt – current, and payment of such amount was made prior to the execution of the February 28, 2020 Loan Agreement. The Loan and Security Agreement matures on March 1, 2024 and will be interest-only through March 1, 2022, followed by 24 equal monthly payments of principal and interest.

Loan and Security Agreement

12 Months Ended

Dec. 31, 2019

7. Loan and Security Agreement

In August 2017, the Company entered into a loan and security agreement with Oxford and SVB under which it borrowed $15.0 million (the “August 2017 Loan”). The loan is due in 30 monthly installments from March 2019 through its repayment in August 2021, with interest-only monthly payments until March 2019. The Company commenced repayment of the loan in March 2019. The August 2017 Loan is secured by all assets of the Company, excluding intellectual property and certain other assets. The August 2017 Loan contains customary affirmative and restrictive covenants, including with respect to fundamental transactions, the incurrence of additional indebtedness, grant liens, pay any dividend or make any distributions to the Company’s holders, make investments, merge or consolidate with any other person, or engage in transactions with its affiliates, but does not include any financial covenants. The loan agreement provides that an event of default will occur if, among other triggers, there occurs any circumstances that could reasonably be expected to result in a material adverse effect on the Company’s business, operations or condition, or on its ability to perform its obligations under the loan. The loan agreement also includes customary representations and warranties, other events of default and termination provisions.

The interest charges on the loan are based on a floating rate that equals the greater of 7.39% or the sum of the 30-day U.S. Dollar London Interbank Offered Rate (“LIBOR”) plus 6.40%. For the year ended December 31, 2019, the average interest rate was 8.72%. In addition, the Company will make a final payment equal to 3.83% of the original principal amount of the loan, or $0.6 million, which will be accrued over the term of the loan using the effective-interest method. As of December 31, 2019, total interest expense accrued was $0.4 million.

In connection with the August 2017 Loan, the Company issued to Oxford and SVB a warrant to purchase the Company’s Series D-2 redeemable convertible preferred stock (the “2017 Warrant”). The 2017 Warrants were later converted into warrants to purchase Series E redeemable convertible preferred stock in May and July 2018, and upon the Company’s IPO on October 1, 2018, all Series E redeemable convertible preferred stock warrants were converted to warrants to purchase 46,359 shares of common stock. The estimated fair value upon issuance of the 2017 Warrant of $0.3 million was recorded as a debt discount on the associated borrowings on the Company’s balance sheet. The debt discount is being amortized to interest expense over the repayment period of the loan using the effective-interest method.

During the years ended December 31, 2019, 2018 and 2017, the Company recorded interest expense related to this loan of $1.1 million, $1.6 million and $0.6 million, respectively. During the years ended December 31, 2019, 2018 and 2017, the Company recorded accretion of debt discount of $0.2 million, $0.2 million and $0.1 million, respectively.

As described in Notes 1 and 15 of these financial statements, the Company entered into a Loan and Security Agreement on February 28, 2020, for gross proceeds of $25 million. Pursuant to the Loan and Security Agreement, $9.6 million of the gross proceeds were used to fully repay the August 2017 Loan. As a result, of the $9.9 million that was outstanding as of December 31, 2019, $8.9 million has been classified on our balance sheet as Debt – non-current. The remaining $1.0 million that was outstanding as of December 31, 2019 has been classified as Debt – current, and payment of such amount was made prior to the execution of the February 28, 2020 Loan Agreement.

The Loan and Security Agreement matures on March 1, 2024 and will be interest-only through March 1, 2022, followed by 24 equal monthly payments of principal and interest.