Related Party Transactions (Details) - Memorial Sloan Kettering Cancer Center [Member]  | 
3 Months Ended | 
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 Mar. 31, 2018  
USD ($) 
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| Receipt of regulatory approval from the U.S. FDA [Member] | |
| Summary of milestone payments related to related party | |
| Milestone payments | $ 1,750,000 | 
| New Drug Application [Member] | |
| Summary of milestone payments related to related party | |
| Milestone payments | $ 750,000 | 
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