Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Aug. 02, 2019
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Entity Registrant Name NANTKWEST, INC.  
Entity Central Index Key 0001326110  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Emerging Growth Company true  
Entity Small Business true  
Entity Ex Transition Period true  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Shell Company false  
Trading Symbol NK  
Title of 12(b) Security Common Stock  
Security Exchange Name NASDAQ  
Entity File Number 1-37507  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 43-1979754  
Entity Address, Address Line One 3530 John Hopkins Court  
Entity Address, City or Town San Diego  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92121  
City Area Code 858  
Local Phone Number 633-0300  
Document Quarterly Report true  
Document Transition Report false  
Entity Common Stock, Shares Outstanding   98,307,859