v3.7.0.1
FAIR VALUE DISCLOSURE (Details) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents $ 19,241 $ 25,244
Total cash equivalents and short-term investments, Amortized Cost 64,892 67,683
Total cash equivalents and short-term investments, Gross Unrealized Gain (Loss) (38) (31)
Total cash equivalents and short-term investments, Fair Value 64,854 67,652
Short-term Investments 45,613 42,408
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents, Amortized Cost 14,249 25,244
Cash equivalents 14,249 25,244
Level 1 | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents, Amortized Cost 14,249 25,244
Cash equivalents 14,249 25,244
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 4,992 0
Short-term investments 50,605 42,408
Securities, Amortized cost 50,643 42,439
Securities, Gross Unrealized Gain (Loss) (38) (31)
Short-term Investments 45,613 42,408
Level 2 | U.S.agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 2,995  
Level 2 | Commercial Paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 1,997  
Level 2 | U.S. treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term investments 22,480 22,497
Securities, Amortized cost 22,507 22,516
Securities, Gross Unrealized Gain (Loss) (27) (19)
Short-term Investments 22,480 22,497
Level 2 | Corporate securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term investments 13,163 7,341
Securities, Amortized cost 13,174 7,353
Securities, Gross Unrealized Gain (Loss) (11) (12)
Short-term Investments 13,163 7,341
Level 2 | U.S.agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term investments 5,991  
Securities, Amortized cost 5,991  
Short-term Investments 2,996  
Level 2 | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Short-term investments 8,971 12,570
Securities, Amortized cost 8,971 12,570
Securities, Gross Unrealized Gain (Loss) 0 0
Short-term Investments $ 6,974 $ 12,570