RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN (Details) (USD $)	12 Months Ended			120 Months Ended	36 Months Ended	32 Months Ended	44 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2007	Apr. 30, 2009	Dec. 31, 2011	Dec. 31, 2012
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty expense	$ 4,519,000	$ 3,273,000	$ 2,073,000
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 - Original Term [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)					3 years
Research and development expense incurred					5,000,000
2006 Research Agreement - Extended Term [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)						4 years
Research and development expense incurred							1,800,000
Maximum obligation	5,800,000
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	4,454,000	3,200,000	2,100,000
Minimum investment per year		$ 800,000