Annual report pursuant to Section 13 and 15(d)

Nature of Operations and Basis of Presentation - Additional Information (Details)

v3.20.1
Nature of Operations and Basis of Presentation - Additional Information (Details)
3 Months Ended 12 Months Ended
Jan. 21, 2020
USD ($)
Debtinstrument
shares
Jun. 26, 2018
USD ($)
$ / shares
shares
May 30, 2018
USD ($)
$ / shares
shares
May 15, 2018
$ / shares
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jul. 16, 2019
USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Reverse share split       0.0636                        
Share consolidation basis nominal value per share | $ / shares       $ 0.01571                        
Share consolidation basis, Renominalisation value per share | $ / shares       $ 0.01                        
Net proceeds from issuance of stock after deducting underwriting discounts,commissions and offering cost   $ 2,400,000 $ 71,800,000                     $ 74,153,000    
Net losses         $ 23,641,000 $ 31,271,000 $ 27,638,000 $ 20,580,000 $ 24,258,000 $ 24,905,000 $ 15,747,000 $ 12,146,000 $ 103,130,000 77,056,000 $ 29,406,000  
Accumulated deficit         $ 234,923,000       $ 131,793,000       $ 234,923,000 $ 131,793,000    
Maximum                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Aggregate initial offering price of securities authorized to issue                               $ 150,000,000
IPO                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Number of shares issued | shares   200,000 6,150,000                          
Offering price per share | $ / shares   $ 13.00 $ 13.00                          
Subsequent Event | Private Placement | Exchangeable Notes                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Aggregate principal amount $ 51,600,000                              
Debt instrument interest rate 6.50%                              
Debt instrument price per unit $ 1,000                              
Subsequent Event | Private Placement | RLNs                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Aggregate principal amount $ 100,000                              
Number of debt instruments within each notes | Debtinstrument 50                              
Debt instrument, aggregate potential payment capped value $ 160,000                              
Debt instrument, aggregate potential payment capped rate 4,000 times                              
Subsequent Event | Private Placement | RLNs | Minimum                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Debt instrument, percentage of net revenue from domestic sale for potential aggregate payments 15.00%                              
Subsequent Event | Private Placement | RLNs | Maximum                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Debt instrument, percentage of net revenue from domestic sale for potential aggregate payments 20.00%                              
Subsequent Event | Private Placement | Securities                                
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                
Debt instrument price per unit $ 1,000                              
Debt instrument, shares embedded within each unit, shares | shares 1,000                              
Debt instrument, shares embedded within each unit, value $ 1,000                              
Proceeds from sale of securities $ 46,700,000