Quarterly report pursuant to Section 13 or 15(d)

Collaborative Arrangements - Textual (Details)

v3.20.1
Collaborative Arrangements - Textual (Details) - USD ($)
1 Months Ended 3 Months Ended 12 Months Ended
Dec. 31, 2019
May 31, 2019
Apr. 30, 2018
Oct. 31, 2017
Dec. 31, 2015
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2018
Dec. 31, 2019
Sep. 30, 2018
Dec. 31, 2017
Aug. 31, 2015
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           $ 14,670,000 $ 15,583,000          
Contract with customer, liability $ 2,044,000         8,536,000     $ 2,044,000      
GSK [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized                 2,000,000.0      
Contract with customer, liability 0         0     0      
GSK [Member] | Minimum [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable           5,750,000            
GSK [Member] | Maximum [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable           38,500,000            
Merck [Member] | Technology Transfer, Collaboration and License Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable                       $ 15,000,000.0
Revenue recognized           900,000 1,000,000.0          
Merck [Member] | Technology Transfer, Collaboration and License Agreement [Member] | Maintenance [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           25,000     900,000      
Contract with customer, liability 0         100,000     0      
Merck [Member] | Supply Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Optional extension period         5 years              
Merck [Member] | Supply Agreement [Member] | Product Sales [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           1,800,000 5,300,000          
Tate & Lyle [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           0            
Tate & Lyle [Member] | Research and Development Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability 0         0     0      
Tate & Lyle [Member] | Supply Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability 2,000,000.0         2,000,000.0     2,000,000.0      
Nestec Ltd. (Nestle Health Sciences) [Member] | Global Development, Option and License Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           0 1,300,000          
Contract with customer, liability $ 13,000     $ 14,000,000.0         13,000      
Nestec Ltd. (Nestle Health Sciences) [Member] | Global Development, Option and License Agreement [Member] | Milestone One [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability       4,000,000.0                
Nestec Ltd. (Nestle Health Sciences) [Member] | Global Development, Option and License Agreement [Member] | Milestone Two [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability       1,000,000.0                
Nestec Ltd. (Nestle Health Sciences) [Member] | Global Development, Option and License Agreement [Member] | Sales-Based Milestone [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Target sales for milestone       1,000,000,000.0                
Nestec Ltd. (Nestle Health Sciences) [Member] | CDX-6114 [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Cumulative catch-up adjustment to revenue, change in measure of progress                 $ 3,000,000.0      
Nestec Ltd. (Nestle Health Sciences) [Member] | Strategic Collaboration Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           1,600,000 1,200,000          
Contract with customer, liability                   $ 600,000 $ 1,200,000  
Nestec Ltd. (Nestle Health Sciences) [Member] | Maximum [Member] | Global Development, Option and License Agreement [Member] | Research and Development Agreement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable       85,000,000.0                
Nestec Ltd. (Nestle Health Sciences) [Member] | Maximum [Member] | Global Development, Option and License Agreement [Member] | Sales-Based Milestone [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable       $ 250,000,000.0                
Porton [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           100,000 $ 0 $ 2,800,000        
Porton [Member] | Milestone One [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability     $ 500,000                  
Number of days for payment     30 days                  
Porton [Member] | Milestone Two [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable     $ 1,500,000                  
Novartis [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           2,400,000            
Contract with customer, liability   $ 5,000,000.0                    
Term of collaborative research and development agreement   20 months                    
Novartis [Member] | Computer Equipment and Software [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent annual receivable increase   $ 8,000,000.0                    
Novartis [Member] | Milestone One [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable   4,000,000.0                    
Novartis [Member] | Milestone Two [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable   $ 5,000,000.0                    
Novartis [Member] | Royalty [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Term of collaborative research and development agreement   20 months                    
Roche [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           700,000            
Roche [Member] | Milestone One [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Number of days for payment 45 days                      
Roche [Member] | Milestone Two [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Number of days for payment 60 days                      
Takeda [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Revenue recognized           2,200,000            
Contract with customer, liability           6,400,000            
Takeda [Member] | Milestone Payment Per Target Gene [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable           100,000,000.0            
Takeda [Member] | Up-front Payment [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contract with customer, liability           8,500,000            
Takeda [Member] | Research and Development Reimbursement [Member]                        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                        
Contingent receivable           $ 22,300,000