Quarterly report pursuant to Section 13 or 15(d)

Debt - Additional Information (Details)

v3.10.0.1
Debt - Additional Information (Details) - USD ($)
9 Months Ended
Apr. 27, 2018
Sep. 30, 2018
Debt Instrument [Line Items]    
Maximum amount available under second draw   $ 15,000,000
Amortization of debt discount and deferred financing costs   $ 174,000
Loan and Security Agreement | Silicon Valley Bank (SVB)    
Debt Instrument [Line Items]    
Loan and security agreement entered date   Apr. 27, 2018
Initial draw amount under agreement $ 15,000,000  
Remaining borrowing facility available date Oct. 31, 2019  
Frequency of amortization payments   Monthly
Date of first required payment of initial draw Nov. 01, 2019  
Extended date of first required payment if second draw funded Apr. 01, 2020  
Minimum fixed interest rate per annum 8.31%  
Final interest rate payment on outstanding principal 4.20%  
Principal and interest payment date Mar. 01, 2022  
Voluntary prepayment fee in first year 3.00%  
Voluntary prepayment fee in second year 2.00%  
Voluntary prepayment fee thereafter 1.00%  
Effective annual interest rate on outstanding debt 10.00%  
Interest expense   $ 639,000
Amortization of debt discount and deferred financing costs   $ 174,000
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 convertible preferred shares 19,890  
Warrants to purchase convertible preferred shares, exercise price $ 18.85