Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.1
License, Clinical Trial and Sponsored Research Agreements (Other - Sponsored Research and Clinical Trial Agreements) (Narrative) (Details) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended
Jul. 01, 2020
Jul. 03, 2017
Nov. 30, 2020
Mar. 31, 2021
Mar. 31, 2020
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]          
Research and development expense       $ 11,618 $ 9,314
Sponsored Research and Clinical Trial Agreements [Member]          
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]          
Research and development expense       1,842 1,349
Fred Hutchinson Cancer Research Center [Member] | Sponsored Research and Clinical Trial Agreements [Member] | CD20 Product or Process [Member]          
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]          
Milestones payable   $ 5,300      
Additional milestone payments     $ 800    
Research and development expense       671 527
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]          
Upfront fees paid $ 1,100        
Research and development expense       $ 104 $ 0