CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS - Short-Term Investments and Marketable Securities (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Schedule Of Short Term Investments And Available For Sale Securities [Line Items]    
Amortized Cost $ 129,912 $ 148,447
Gross Unrealized Gains 0 0
Gross Unrealized Losses 17 64
Fair Value 129,895 148,383
Commercial Paper    
Schedule Of Short Term Investments And Available For Sale Securities [Line Items]    
Amortized Cost 129,912 148,447
Gross Unrealized Gains 0 0
Gross Unrealized Losses 17 64
Fair Value $ 129,895 $ 148,383