Annual report pursuant to Section 13 and 15(d)

Debt - Additional Information (Details)

v3.20.1
Debt - Additional Information (Details) - USD ($)
 12 Months Ended
Apr. 27, 2018
Dec. 31, 2019
Dec. 31, 2018
Debt Instrument [Line Items]      
Accretion of debt discounts and deferred financing costs   $ 362,000 $ 360,000
Ordinary Shares      
Debt Instrument [Line Items]      
Number of warrants to purchase preferred shares 19,890    
Loan and Security Agreement | Silicon Valley Bank (SVB)      
Debt Instrument [Line Items]      
Loan and security agreement entered date   Apr. 27, 2018  
Funded amount under agreement $ 15,000,000    
Remaining borrowing facility available date Oct. 31, 2019    
Maximum amount available under agreement $ 30,000,000    
Non-utilization fee percentage of undrawn principal amount 1.50%    
Frequency of amortization payments     Monthly
Date of first required payment of initial draw Nov. 01, 2019    
Minimum fixed interest rate per annum 8.31%    
Final interest rate payment on outstanding principal 4.20%    
Principal and interest payment, maturity date Mar. 01, 2022    
Final payment fee $ 630,000    
Prepayment fee in first year 4.00%    
Prepayment fee in second year 3.00%    
Prepayment fee thereafter 2.00%    
Principal payment during the period $ 1,034,000    
Effective annual interest rate on outstanding debt   11.28%  
Interest expense   $ 1,761,000 $ 1,169,000
Accretion of debt discounts and deferred financing costs   $ 362,000 $ 360,000
Loan and Security Agreement | Silicon Valley Bank (SVB) | Wall Street Journal Prime Rate      
Debt Instrument [Line Items]      
Basis spread on interest rate 3.89%    
Loan and Security Agreement | Silicon Valley Bank (SVB) | Maximum      
Debt Instrument [Line Items]      
Maximum amount available under second draw $ 15,000,000    
Silicon Valley Bank and Life Sciences Fund II LLC      
Debt Instrument [Line Items]      
Percentage of purchase additional ordinary shares equal to term loan divided by applicable exercise price 2.50%    
Silicon Valley Bank and Life Sciences Fund II LLC | Series B Convertible Preferred Shares      
Debt Instrument [Line Items]      
Number of warrants to purchase preferred shares 19,890    
Warrants to purchase preferred shares, exercise price $ 18.85