Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Narrative (Details)

v3.20.4
Summary of Significant Accounting Policies - Narrative (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2020
USD ($)
segment
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Property, Plant and Equipment [Line Items]      
Number of operating segments | segment 1    
Cash and cash equivalents $ 272,350 $ 306,019  
Allowance for doubtful accounts 0 0 $ 0
Asset impairment charges 0 0 0
Research and development 50,327 52,866 $ 41,382
Inventory $ 13,927 $ 0  
Minimum      
Property, Plant and Equipment [Line Items]      
Lease term 12 months    
Maximum      
Property, Plant and Equipment [Line Items]      
Lease term 128 months    
Acquired intellectual property and reacquired rights | Minimum      
Property, Plant and Equipment [Line Items]      
Acquired intangible assets useful life 10 years    
Acquired intellectual property and reacquired rights | Maximum      
Property, Plant and Equipment [Line Items]      
Acquired intangible assets useful life 20 years