RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN - Additional Information (Details) - USD ($)	3 Months Ended		36 Months Ended	120 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Apr. 30, 2009	Jul. 31, 2007
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty expense	$ 3,284,000	$ 2,537,000
1997 Research Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)				10 years
2006 Research Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)			3 years
Research agreement, extension term (in years)	2 years
Research agreement, date on which recent amendment completed	Mar. 13, 2020
Research agreement, new amendment expiration date	Apr. 30, 2023
Maximum obligation	$ 9,100,000
Research and development expense incurred	$ 272,000	243,000
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%
Minimum royalty payment per year	$ 100,000
Royalty expense	3,300,000	$ 2,500,000
Minimum investment per year	$ 800,000