Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Narrative (Details)

v3.20.1
Commitments and Contingencies - Narrative (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
ft²
Dec. 31, 2019
USD ($)
ft²
extension_option
lease_agreement
Dec. 31, 2018
USD ($)
Loss Contingencies [Line Items]        
Lease term     12 years 6 months  
Rent expense | $ $ 11.5     $ 0.5
Lease Liabilities | $     $ 0.5  
Freising, Germany        
Loss Contingencies [Line Items]        
Number of lease agreements | lease_agreement     4  
Area of leased property     19,000  
Boston, Massachusetts        
Loss Contingencies [Line Items]        
Area of leased property     3,950  
Hallbergmoos, Germany        
Loss Contingencies [Line Items]        
Area of leased property   105,000    
Number of agreement extension options | extension_option     2  
Lease extension term     60 months  
Rent expense | $     $ 0.2  
Security deposit | $   $ 0.8   $ 0.8
Leases in Same Building | Freising, Germany        
Loss Contingencies [Line Items]        
Number of lease agreements | lease_agreement     3  
Leases Expected to be Delivered by December 2019 | Hallbergmoos, Germany        
Loss Contingencies [Line Items]        
Area of leased property   96,400    
Leases Expected to be Delivered by May 2020 | Hallbergmoos, Germany        
Loss Contingencies [Line Items]        
Area of leased property   8,600    
Leases Expected to be Delivered by October 2024 | Hallbergmoos, Germany        
Loss Contingencies [Line Items]        
Area of leased property   22,300    
Leases with First Right of Refusal for Additional Area | Hallbergmoos, Germany        
Loss Contingencies [Line Items]        
Area of leased property   13,400