FAIR VALUE MEASUREMENT - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	Oct. 05, 2015
Liabilities [Abstract]
Contingent consideration liability		$ 152,070	$ 166,800	$ 166,800
Recurring [Member]
ASSETS
Cash equivalents	[1]	118,792	147,007
Total		118,792	147,007
Liabilities [Abstract]
Contingent consideration liability		152,070	166,800
Total		152,070	166,800
Recurring [Member] | Level 1 [Member]
ASSETS
Cash equivalents	[1]	118,792	147,007
Total		118,792	147,007
Liabilities [Abstract]
Contingent consideration liability		0	0
Total		0	0
Recurring [Member] | Level 2 [Member]
ASSETS
Cash equivalents	[1]	0	0
Total		0	0
Liabilities [Abstract]
Contingent consideration liability		0	0
Total		0	0
Recurring [Member] | Level 3 [Member]
ASSETS
Cash equivalents	[1]	0	0
Total		0	0
Liabilities [Abstract]
Contingent consideration liability		152,070	166,800
Total		$ 152,070	$ 166,800

[1] Cash equivalents represent the fair value of the Company’s investments in money market funds at March 31, 2016 and December 31, 2015.