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RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Research And Development Arrangement Contract To Perform For Others [Line Items]      
Royalty expense $ 11,125,000 $ 11,776,000 $ 6,996,000
Maximum obligation 6,900,000    
Research and development expense incurred $ 1,200,000 997,000 1,100,000
1997 Amended License Agreement [Member]      
Research And Development Arrangement Contract To Perform For Others [Line Items]      
Royalty rate for licensed products sold by the Company (in hundredths) 3.00%    
Royalty rate for licensed products sold by the Company's sublicenses (in hundredths) 3.00%    
Royalty expense $ 11,100,000 $ 11,800,000 $ 7,000,000.0