RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty expense	$ 258,000	$ 3,293,000	$ 519,000	$ 8,195,000
1997 Amended License Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty expense	258,000	3,300,000	$ 519,000	8,200,000
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%
2006 Research Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research agreement, extension term (in years)			2 years
Research agreement, new amendment expiration date			Apr. 30, 2023
Maximum obligation	4,500,000		$ 4,500,000
Research and development expense incurred	$ 384,000	$ 309,000	$ 1,100,000	$ 890,000