Annual report pursuant to Section 13 and 15(d)

Revenue - Collaboration Agreement - Performance obligations (Details)

v3.20.4
Revenue - Collaboration Agreement - Performance obligations (Details)
 12 Months Ended
Jan. 13, 2020
USD ($)
item
Dec. 31, 2020
USD ($)
item
Performance obligations    
Number of independent targets | item   2
Astellas Collaboration Agreement    
Performance obligations    
Number of co-development targets 3 3
Number of independent targets | item 2 2
Amount of transaction price of the agreement at inception $ 50,000,000  
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   $ 62,800,000
Astellas Collaboration Agreement | Rights granted, first independent target    
Performance obligations    
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   15,200,000
Astellas Collaboration Agreement | Rights granted, second independent target    
Performance obligations    
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   15,200,000
Astellas Collaboration Agreement | Research services and rights granted under the co-exclusive license, first co-development target    
Performance obligations    
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   7,300,000
Astellas Collaboration Agreement | Research services and rights under the co-exclusive license, second co-development target    
Performance obligations    
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   7,300,000
Astellas Collaboration Agreement | Research services and rights under the co-exclusive license, third co-development target    
Performance obligations    
Amount of transaction price allocated to performance obligation that has not been recognized as revenue   $ 17,800,000