Property and equipment, net (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2019
Property and equipment, net    
Total property and equipment $ 8,040 $ 9,087
Accumulated depreciation and amortization (5,458) (6,470)
Property and equipment, net 2,582 2,617
Depreciation and amortization 700  
Laboratory equipment    
Property and equipment, net    
Total property and equipment 3,761 4,125
Internally developed software    
Property and equipment, net    
Total property and equipment 1,970 2,547
Depreciation and amortization 400  
Leasehold improvements    
Property and equipment, net    
Total property and equipment 1,524 1,524
Furniture and office equipment    
Property and equipment, net    
Total property and equipment 447 456
Computer hardware    
Property and equipment, net    
Total property and equipment 338 338
Internally developed software in progress    
Property and equipment, net    
Total property and equipment $ 0 $ 97