CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS - Summary of Cash, Cash Equivalents, Short-Term Investments and Marketable Securities (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Cash and cash equivalents:        
Cash $ 58,964 $ 73,495    
Cash equivalents:        
Commercial paper 28,598 19,996    
Money market mutual funds 121,463 88,568    
Total cash and cash equivalents 209,025 182,059 167,908 343,637
Short-term investments:        
Short-term investments 129,895 148,383    
Total cash, cash equivalents, and short-term investments 338,920 330,442    
Commercial paper        
Short-term investments:        
Short-term investments $ 129,895 $ 148,383