Annual report pursuant to Section 13 and 15(d)

License, Clinical Trial and Sponsored Research Agreements (Other - Sponsored Research and Clinical Trial Agreements) (Narrative) (Details)

v3.22.1
License, Clinical Trial and Sponsored Research Agreements (Other - Sponsored Research and Clinical Trial Agreements) (Narrative) (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Sep. 08, 2021
Apr. 01, 2021
Jul. 03, 2017
Jun. 30, 2021
Nov. 30, 2020
Jun. 30, 2020
Dec. 31, 2021
Dec. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Research and development expense             $ 49,864 $ 37,237
Sponsored Research and Clinical Trial Agreements [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Research and development expense             6,591 7,717
Fred Hutchinson Cancer Research Center [Member] | Sponsored Research and Clinical Trial Agreements [Member] | CD20 (MB-106) [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Milestones payable     $ 5,300          
Additional milestone payments         $ 1,800      
Research and development expense             1,979 1,804
Fred Hutchinson Cancer Research Center [Member] | Clinical Trial Agreements [Member] | CD20 (MB-106) [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Research and development expense             2,000 1,800
St. Jude Children's Research Hospital [Member] | Sponsored Research and Clinical Trial Agreements [Member] | ST. Jude - XSCID [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Research and development expense             865 1,842
St. Jude Children's Research Hospital [Member] | Data Transfer Agreement [Member] | ST. Jude - XSCID [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Upfront fees paid           $ 1,100    
Research and development expense             900 1,800
Mayo Clinic [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Upfront fees paid   $ 800            
Mayo Clinic [Member] | Sponsored Research and Clinical Trial Agreements [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Milestones payable       $ 2,100        
Research and development expense             695 0
Agreement term       2 years        
Leiden University Medical Centre [Member] | Sponsored Research and Clinical Trial Agreements [Member] | RAG1 SCID (MB-110) [Member]                
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                
Milestones payable $ 500              
Research and development expense             $ 170 $ 0
Agreement term 5 years