XML 70 R32.htm IDEA: XBRL DOCUMENT v3.19.3
Summary of Significant Accounting Policies - Additional Information (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
May 01, 2019
Aug. 12, 2013
ft²
Sep. 30, 2019
USD ($)
Customer
Sep. 30, 2018
USD ($)
Customer
Sep. 30, 2019
USD ($)
Customer
Sep. 30, 2018
USD ($)
Customer
Dec. 31, 2018
USD ($)
Customer
Aug. 30, 2019
ft²
Jan. 01, 2019
USD ($)
Jun. 19, 2018
ft²
Jul. 30, 2016
ft²
Oct. 08, 2014
ft²
Summary Of Significant Accounting Policies [Line Items]                        
Description of significant off-balance sheet risk         The Company has no significant off‑balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements.              
Performance obligation unsatisfied     $ 2,865   $ 2,865              
Revenue recognized         8,811              
Restricted cash     2,164   2,164   $ 2,671          
Net lease assets     56,439   56,439              
Lease liabilities     65,629   65,629              
Lease costs     $ 2,514 $ 1,610 $ 7,404 $ 4,796            
Weighted average remaining lease term     9 years 4 months 24 days   9 years 4 months 24 days              
Weighted average discount rate     5.30%   5.30%              
Future minimum lease payments for leases signed but not yet commenced     $ 14,089   $ 14,089              
Implementation costs associated with service contracts     $ 2,943   $ 2,943              
ASC 842                        
Summary Of Significant Accounting Policies [Line Items]                        
Net lease assets                 $ 52,334      
Lease liabilities                 $ 63,280      
Cambridge, Massachusetts at 55 Cambridge Parkway                        
Summary Of Significant Accounting Policies [Line Items]                        
Operating lease of office space | ft²               36,689     51,923  
Operating lease, option to extend         option to extend the lease term with respect to a portion of the office space for an additional period of five-years              
Needham, Massachusetts                        
Summary Of Significant Accounting Policies [Line Items]                        
Lessee, operating lease, renewal term 1 year                      
Lessee, operating lease, existence of option to terminate true                      
Cambridge, Massachusetts at 121 First St.                        
Summary Of Significant Accounting Policies [Line Items]                        
Operating lease of office space | ft²                   48,393    
Operating lease, option to extend         option to extend the lease term for two additional periods of five years each              
Dublin, Ireland                        
Summary Of Significant Accounting Policies [Line Items]                        
Operating lease of office space | ft²   13,345                    
Operating lease, rent increasing year   5 years                    
Cambridge, Massachusetts at 2 Canal Park                        
Summary Of Significant Accounting Policies [Line Items]                        
Operating lease of office space | ft²                       48,059
Operating lease, option to extend         option to extend the lease term for one additional period of five years              
Sales Revenue, Net | Concentration of Credit Risk                        
Summary Of Significant Accounting Policies [Line Items]                        
Concentration of credit risk, percentage     10.00% 10.00% 10.00% 10.00%            
Number of major customers | Customer     0 0 0 0            
Net Accounts Receivable | Advertising Customers                        
Summary Of Significant Accounting Policies [Line Items]                        
Unbilled accounts receivable     $ 6,509   $ 6,509   $ 5,815          
Net Accounts Receivable | Concentration of Credit Risk                        
Summary Of Significant Accounting Policies [Line Items]                        
Number of major customers | Customer         0   0          
Net Accounts Receivable | Concentration of Credit Risk | Customer One                        
Summary Of Significant Accounting Policies [Line Items]                        
Concentration of credit risk, percentage         26.00%   21.00%          
Net Accounts Receivable | Concentration of Credit Risk | Customer Two                        
Summary Of Significant Accounting Policies [Line Items]                        
Concentration of credit risk, percentage             14.00%