Term Loan	12 Months Ended
Dec. 31, 2020
Debt Disclosure [Abstract]
Term Loan	6. Term Loan Loan and Security Agreement In April 2020, the Company and certain of its subsidiaries entered into a Loan and Security Agreement (the “Loan Agreement”) with the lenders referred to therein (the “Lenders”), and Silicon Valley Bank, as collateral agent. The Loan Agreement provides for (i) a secured term A loan facility (the “Term A Loan Facility”) of up to $10.0 million and (ii) a secured term B loan facility (the “Term B Loan Facility”) of up to $5.0 million that is available upon the Company satisfying certain milestones. The Term A Loan Facility matures on November 1, 2022, provided, that if the Term B Loan Facility is funded, the facilities instead mature on September 1, 2023. The loans will bear interest at the greater of (i) 4.50% and (ii) the sum of (a) the Prime Rate as reported in The Wall Street Journal plus (b) 1.25%. As of December 31, 2020, the Company had not drawn any amount under the Loan Agreement. In connection with the execution of the Loan Agreement, the Company agreed to issue the Lenders warrants to purchase shares of the Company’s common stock. In April 2020, the Company issued Silicon Valley Bank a warrant to purchase 25,000 shares of the Company’s common stock with a warrant exercise price of $22.06 per share that is immediately exercisable. The initial expiration date of April 7, 2030 was changed to June 30, 2025 in connection with the July 2020 offering. The Company determined the fair value of the warrant at the issuance date by using the Black-Scholes option-pricing model with the following assumptions: risk-free interest rate of 0.75%, no dividends, expected volatility of 92.3% and expected term of 10.0 years. Upon issuance, the fair value allocated to the warrant of $0.6 million was recorded as a debt issuance cost and classified within other assets and met the requirements for equity classification within additional paid-in capital on the consolidated balance sheets. An additional warrant to purchase 8,333 shares of the Company’s common stock will be issued in connection with the Term B Loan Facility, if funded, with the exercise price determined on the Company’s stock price at the time of issuance. Additionally, the Company incurred $0.2 million in closing costs that were recorded as debt issuance costs and classified within other assets on the consolidated balance sheets. The deferred assets related to the debt issuance cost and warrant are recognized as interest expense over the duration of the Loan Agreement and are recorded within other expenses, net on the consolidated statements of operations and comprehensive loss. As of December 31, 2020, the remaining unamortized debt issuance costs classified within other assets on the consolidated balance sheet is $0.6 million.

Term Loan

12 Months Ended

Dec. 31, 2020

6. Term Loan

Loan and Security Agreement

In April 2020, the Company and certain of its subsidiaries entered into a Loan and Security Agreement (the “Loan Agreement”) with the lenders referred to therein (the “Lenders”), and Silicon Valley Bank, as collateral agent. The Loan Agreement provides for (i) a secured term A loan facility (the “Term A Loan Facility”) of up to $10.0 million and (ii) a secured term B loan facility (the “Term B Loan Facility”) of up to $5.0 million that is available upon the Company satisfying certain milestones. The Term A Loan Facility matures on November 1, 2022, provided, that if the Term B Loan Facility is funded, the facilities instead mature on September 1, 2023. The loans will bear interest at the greater of (i) 4.50% and (ii) the sum of (a) the Prime Rate as reported in The Wall Street Journal plus (b) 1.25%. As of December 31, 2020, the Company had not drawn any amount under the Loan Agreement.

In connection with the execution of the Loan Agreement, the Company agreed to issue the Lenders warrants to purchase shares of the Company’s common stock. In April 2020, the Company issued Silicon Valley Bank a warrant to purchase 25,000 shares of the Company’s common stock with a warrant exercise price of $22.06 per share that is immediately exercisable. The initial expiration date of April 7, 2030 was changed to June 30, 2025 in connection with the July 2020 offering. The Company determined the fair value of the warrant at the issuance date by using the Black-Scholes option-pricing model with the following assumptions: risk-free interest rate of 0.75%, no dividends, expected volatility of 92.3% and expected term of 10.0 years. Upon issuance, the fair value allocated to the warrant of $0.6 million was recorded as a debt issuance cost and classified within other assets and met the requirements for equity classification within additional paid-in capital on the consolidated balance sheets. An additional warrant to purchase 8,333 shares of the Company’s common stock will be issued in connection with the Term B Loan Facility, if funded, with the exercise price determined on the Company’s stock price at the time of issuance.

Additionally, the Company incurred $0.2 million in closing costs that were recorded as debt issuance costs and classified within other assets on the consolidated balance sheets.

The deferred assets related to the debt issuance cost and warrant are recognized as interest expense over the duration of the Loan Agreement and are recorded within other expenses, net on the consolidated statements of operations and comprehensive loss. As of December 31, 2020, the remaining unamortized debt issuance costs classified within other assets on the consolidated balance sheet is $0.6 million.