Term Loan	9 Months Ended
Sep. 30, 2021
Term Loan [Abstract]
Term Loan	9. Term Loan The Company has a Loan and Security Agreement dated as of April 28, 2020 with Pacific Western Bank (PacWest or the Bank) for an initial term loan limit 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%. As of September 30, 2021, no amounts had been drawn under the Loan Agreement and the deferred debt issuance costs were $0.1 million and are included in other noncurrent assets on the Company’s consolidated balance sheets. On October 21, 2021, the Company entered into a Fourth Amendment of the Loan Agreement (the Loan Amendment) under which the Bank will provide one or more term loans (the Term Loans), as well as certain non-formula ancillary services, which shall not exceed $5.5 million in the aggregate. The aggregate sum of the outstanding Term Loans and non-formula ancillary services shall at no time exceed $15.0 million, with each term loan to be in an amount of not less than $1.0 million. Pursuant to the Loan Amendment, the interest rate for the Term Loans shall be set at an annual rate equal to the greater of (i) 0.25% above the Prime Rate then in effect and (ii) 4.25%. Other than as disclosed in this Quarterly Report on Form 10-Q, there have been no material changes in the Loan Agreement from those disclosed in Note 9 to consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2020.

Term Loan

9 Months Ended

Sep. 30, 2021

9. Term Loan

The Company has a Loan and Security Agreement dated as of April 28, 2020 with Pacific Western Bank (PacWest or the Bank) for an initial term loan limit 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%. As of September 30, 2021, no amounts had been drawn under the Loan Agreement and the deferred debt issuance costs were $0.1 million and are included in other noncurrent assets on the Company’s consolidated balance sheets.

On October 21, 2021, the Company entered into a Fourth Amendment of the Loan Agreement (the Loan Amendment) under which the Bank will provide one or more term loans (the Term Loans), as well as certain non-formula ancillary services, which shall not exceed $5.5 million in the aggregate. The aggregate sum of the outstanding Term Loans and non-formula ancillary services shall at no time exceed $15.0 million, with each term loan to be in an amount of not less than $1.0 million. Pursuant to the Loan Amendment, the interest rate for the Term Loans shall be set at an annual rate equal to the greater of (i) 0.25% above the Prime Rate then in effect and (ii) 4.25%. Other than as disclosed in this Quarterly Report on Form 10-Q, there have been no material changes in the Loan Agreement from those disclosed in Note 9 to consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2020.