Term Loan	12 Months Ended
Dec. 31, 2020
Term Loan [Abstract]
Term Loan	9. Term Loan On April 28, 2020, the Company entered into a Loan and Security Agreement with Pacific Western Bank for a term loan not exceeding $12.0 million (the Loan Agreement) to finance leasehold improvements for the facilities in Redwood City, CA and other purposes permitted under the Loan Agreement, with an interest rate equal to the greater of 0.25% above the Prime Rate (as defined in the Loan Agreement) or 5.00%. The Loan Agreement granted to Pacific Western Bank a security interest on substantially all of the Company’s assets other than intellectual property to secure the performance of the Company’s obligations under the Loan Agreement, and contains a variety of affirmative and negative covenants, including required financial reporting, limitations on certain dispositions of assets or distributions, limitations on the incurrence of additional debt or liens and other customary requirements. As of December 31, 2020, the Company was in compliance with such covenants and had no indebtedness outstanding under the Loan Agreement. In connection with the entrance into the Loan Agreement, the Company issued Pacific Western Bank a warrant to purchase shares of its Series B redeemable convertible preferred stock at an exercise price of $1.4034 per share (the Existing PacWest Warrant). The Existing PacWest Warrant was initially exercisable for 42,753 shares of the Company’s Series B redeemable convertible preferred stock (not adjusted for the Exchange Ratio). Pursuant to the terms of the Existing PacWest Warrant and the Merger agreement (see Note 3), at the Effective Time of the Merger, the Company issued a new common stock warrant to Pacific Western Bank (the New PacWest Warrant) which replaced the Existing PacWest Warrant. The New PacWest Warrant is initially exercisable solely for 5,301 shares of the Company’s common stock and will be exercisable for an additional number of shares of the Company’s common stock equal to 1.00% of the aggregate original principal amount of all term loans made pursuant to the Loan Agreement (up to an aggregate maximum of 15,903 shares of the Company’s common stock). Any restriction on the exercise set forth in the Existing PacWest Warrant are in full force and effect in the New PacWest Warrant and the term, exercisability, vesting schedule and other provisions of the Existing PacWest warrant otherwise remain unchanged in the New PacWest Warrant. Further, the New PacWest Warrant to purchase 5,301 shares of the Company’s common stock is immediately exercisable. See Note 15 for further discussion regarding terms of warrants. The New PacWest Warrant was exercised in February 2021. The Company may request to draw upon the term loan at any time through the date eighteen months after the date of the Loan Agreement (Availability End Date), which is October 28, 2021. As of December 31, 2020, no amounts have been drawn under the Loan Agreement. At issuance, the Company accounted for the fair value of the Existing PacWest Warrant, determined to be $0.1 million, as a liability and as a corresponding deferred debt issuance cost which was amortized on a straight-line basis until the Availability End Date in interest expenses. The liability was adjusted to fair value each reporting period through earnings. Upon issuance of the New PacWest Warrant, the liability was reclassified to additional paid-in capital and is no longer subject to remeasurement at fair value. The fair value of the New PacWest Warrant was equal to the fair value of the Existing PacWest Warrant on the Merger date. Accordingly, no incremental expense was recognized at the Merger date. Upon each draw of the term loan, the Company will derecognize the proportionate unamortized amount of the deferred asset and account for it as a debt discount to the drawn term loan. The debt discount will be presented in the consolidated balance sheet as a direct adjustment to the carrying value of the term loan. The debt discount will be amortized using the effective interest rate method over the term of the debt and recorded as an interest expense. As of December 31, 2020, the deferred debt issuance costs were $0.2 million and are included in other non-current assets on the Company’s consolidated balance sheets.

Term Loan

12 Months Ended

Dec. 31, 2020

9. Term Loan

On April 28, 2020, the Company entered into a Loan and Security Agreement with Pacific Western Bank for a term loan not exceeding $12.0 million (the Loan Agreement) to finance leasehold improvements for the facilities in Redwood City, CA and other purposes permitted under the Loan Agreement, with an interest rate equal to the greater of 0.25% above the Prime Rate (as defined in the Loan Agreement) or 5.00%. The Loan Agreement granted to Pacific Western Bank a security interest on substantially all of the Company’s assets other than intellectual property to secure the performance of the Company’s obligations under the Loan Agreement, and contains a variety of affirmative and negative covenants, including required financial reporting, limitations on certain dispositions of assets or distributions, limitations on the incurrence of additional debt or liens and other customary requirements. As of December 31, 2020, the Company was in compliance with such covenants and had no indebtedness outstanding under the Loan Agreement.

In connection with the entrance into the Loan Agreement, the Company issued Pacific Western Bank a warrant to purchase shares of its Series B redeemable convertible preferred stock at an exercise price of $1.4034 per share (the Existing PacWest Warrant). The Existing PacWest Warrant was initially exercisable for 42,753 shares of the Company’s Series B redeemable convertible preferred stock (not adjusted for the Exchange Ratio). Pursuant to the terms of the Existing PacWest Warrant and the Merger agreement (see Note 3), at the Effective Time of the Merger, the Company issued a new common stock warrant to Pacific Western Bank (the New PacWest Warrant) which replaced the Existing PacWest Warrant. The New PacWest Warrant is initially exercisable solely for 5,301 shares of the Company’s common stock and will be exercisable for an additional number of shares of the Company’s common stock equal to 1.00% of the aggregate original principal amount of all term loans made pursuant to the Loan Agreement (up to an aggregate maximum of 15,903 shares of the Company’s common stock). Any restriction on the exercise set forth in the Existing PacWest Warrant are in full force and effect in the New PacWest Warrant and the term, exercisability, vesting schedule and other provisions of the Existing PacWest warrant otherwise remain unchanged in the New PacWest Warrant. Further, the New PacWest Warrant to purchase 5,301 shares of the Company’s common stock is immediately exercisable. See Note 15 for further discussion regarding terms of warrants. The New PacWest Warrant was exercised in February 2021.

The Company may request to draw upon the term loan at any time through the date eighteen months after the date of the Loan Agreement (Availability End Date), which is October 28, 2021. As of December 31, 2020, no amounts have been drawn under the Loan Agreement.

At issuance, the Company accounted for the fair value of the Existing PacWest Warrant, determined to be $0.1 million, as a liability and as a corresponding deferred debt issuance cost which was amortized on a straight-line basis until the Availability End Date in interest expenses. The liability was adjusted to fair value each reporting period through earnings. Upon issuance of the New PacWest Warrant, the liability was reclassified to additional paid-in capital and is no longer subject to remeasurement at fair value. The fair value of the New PacWest Warrant was equal to the fair value of the Existing PacWest Warrant on the Merger date. Accordingly, no incremental expense was recognized at the Merger date.

Upon each draw of the term loan, the Company will derecognize the proportionate unamortized amount of the deferred asset and account for it as a debt discount to the drawn term loan. The debt discount will be presented in the consolidated balance sheet as a direct adjustment to the carrying value of the term loan. The debt discount will be amortized using the effective interest rate method over the term of the debt and recorded as an interest expense.

As of December 31, 2020, the deferred debt issuance costs were $0.2 million and are included in other non-current assets on the Company’s consolidated balance sheets.