Annual report pursuant to Section 13 and 15(d)

FAIR VALUE (Details)

v3.3.1.900
FAIR VALUE (Details) - Fair Value Measurements Recurring - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value $ 124,158 $ 142,984
Money Market Funds | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 26,291 10,027
U S Treasury Securities | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 9,048 2,010
U S Government Sponsored Enterprises Debt Securities | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 48,613 45,786
Corporate Bond Securities And Commercial Paper | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 40,206 85,161
Fair Value Inputs Level1    
Fair Value    
Investments at fair value 26,291 10,027
Fair Value Inputs Level1 | Money Market Funds    
Fair Value    
Investments at fair value 26,291 10,027
Fair Value Inputs Level2    
Fair Value    
Investments at fair value 97,867 132,957
Fair Value Inputs Level2 | U S Treasury Securities    
Fair Value    
Investments at fair value 9,048 2,010
Fair Value Inputs Level2 | U S Government Sponsored Enterprises Debt Securities    
Fair Value    
Investments at fair value 48,613 45,786
Fair Value Inputs Level2 | Corporate Bond Securities And Commercial Paper    
Fair Value    
Investments at fair value $ 40,206 $ 85,161