STOCKHOLDERS' EQUITY AND SHARE-BASED COMPENSATION EXPENSE - Share-based compensation expense (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	$ 12,411,000		$ 7,727,000		$ 17,207,000
Share based compensation expense related to acquisition					8,300,000
Costs of product sales [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	2,500,000		1,002,000		1,554,000
Research and development [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	2,266,000		1,331,000		1,337,000
Selling, general and administrative [Member]
Recognized share-based compensation expense [Abstract]
Total stock-based compensation expense	$ 7,645,000	[1]	$ 5,394,000	[1]	$ 14,316,000	[1]

[1] Includes $8.3 million of share-based compensation expense related to the acceleration of unvested stock options in connection with the Acquisition during the year ended December 31, 2012.