Quarterly report pursuant to Section 13 or 15(d)

Loan and Security Agreement - Additional Information (Details)

v3.20.2
Loan and Security Agreement - Additional Information (Details)
1 Months Ended 3 Months Ended 6 Months Ended
Feb. 29, 2020
USD ($)
Installment
$ / shares
shares
Aug. 31, 2017
USD ($)
Installment
Jun. 30, 2020
USD ($)
Jun. 30, 2019
USD ($)
Jun. 30, 2020
USD ($)
Jun. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Oct. 01, 2018
shares
Jul. 31, 2018
USD ($)
Debt Instrument [Line Items]                  
Interest payable     $ 200,000   $ 200,000   $ 400,000    
Debt, non-current     24,281,000   24,281,000   8,876,000    
Loan and accretion of debt discount     100,000 $ 85,000 200,000 $ 175,000      
Interest expense, debt     $ 600,000 $ 300,000 $ 1,000,000.0 $ 600,000      
Average interest rate     8.07% 8.87% 8.08% 8.88%      
Two Thousand Seventeen Warrants                  
Debt Instrument [Line Items]                  
Estimated fair value portion of preferred stock                 $ 300,000
Series E Redeemable Convertible Preferred Stock                  
Debt Instrument [Line Items]                  
Warrant to purchase stock | shares               46,359  
August 2017 Loan | Floating Rate                  
Debt Instrument [Line Items]                  
Interest charges on loan   7.39%              
August 2017 Loan | LIBOR                  
Debt Instrument [Line Items]                  
Interest charges on loan   6.40%              
Description of interest charges on loan         the sum of the 30-day U.S. Dollar London Interbank Offered Rate (“LIBOR”) plus 6.40%.        
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank                  
Debt Instrument [Line Items]                  
Warrant to purchase stock | shares 81,257                
Exercise price per share | $ / shares $ 9.23                
Estimated fair value upon issuance of warrants $ 600,000                
Debt, non-current     $ 25,000,000.0   $ 25,000,000.0        
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | August 2017 Loan                  
Debt Instrument [Line Items]                  
Borrowed amount   $ 15,000,000.0              
Debt outstanding amount             $ 10,000,000.0    
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | August 2017 Loan | March 2019                  
Debt Instrument [Line Items]                  
Number of monthly installments | Installment   30              
Payment terms, description         The loan was due in 30 monthly installments from March 2019        
Repayment installment, start date, month and year   2019-03              
Repayment installment, end date, month and year   2021-08              
Frequency of interest-only payments         monthly payments        
Interest-only payments, maturity month and year   2019-03              
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | Term A Loan                  
Debt Instrument [Line Items]                  
Borrowed amount 25,000,000.0                
Term loan maximum borrowing capacity 25,000,000.0                
Repayment of outstanding principal amount $ 9,600,000                
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | Term Loans                  
Debt Instrument [Line Items]                  
Number of monthly installments | Installment 24                
Payment terms, description         The Term Loans mature on March 1, 2024 (the “Maturity Date”) and will be interest-only through March 1, 2022, followed by 24 equal monthly payments of principal and interest.        
Interest charges on loan 8.07%                
Description of interest charges on loan         The Term Loans will bear interest at a floating per annum rate equal to the greater of (i) 8.07% or (ii) the sum of (a) the greater of (1) the thirty (30) day U.S. LIBOR rate reported in the Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue or (2) 1.67%, plus (b) 6.40%.        
Debt instrument, maturity date Mar. 01, 2024                
Debt instrument interest only payments maturity date Mar. 01, 2022                
Floor percent of thirty days libor 1.67%                
Final payment fee percentage 3.83%                
Interest payable $ 1,000,000.0                
Principal amount Prepayment amount percentage to be paid before first anniversary 3.00%                
Principal amount Prepayment amount percentage to be paid between first and second anniversary 2.00%                
Principal amount Prepayment amount percentage to be paid to be paid thereafter and prior to maturity 1.00%                
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | Term Loans | Maximum                  
Debt Instrument [Line Items]                  
Additional borrowing amount $ 5,000,000.0                
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | Term Loans | LIBOR                  
Debt Instrument [Line Items]                  
Interest charges on loan 6.40%                
Loan and Security Agreement | Oxford Finance LLC and Silicon Valley Bank | Term B Loan | Minimum                  
Debt Instrument [Line Items]                  
Upfront payment received $ 50,000,000.0