v3.6.0.2
FAIR VALUE DISCLOSURE (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents, at Carrying Value $ 25,244 $ 33,436
Cash equivalents 25,244 33,436
Short-term investments 42,408 46,593
Cash, Cash Equivalents, and Short-term Investments 67,683 80,090
Cash, Cash Equivalents, and Short-term Investments, Accumulated Gross Unrealized Gain (Loss), before Tax (31) (61)
Cash, Cash Equivalents, and Short-term Investments, Fair Value 67,652 80,029
Level 1 | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash Equivalents, at Carrying Value 25,244 33,436
Cash equivalents 25,244 33,436
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Debt Securities, Amortized Cost Basis 42,439 46,654
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax (31) (61)
Short-term investments 42,408 46,593
Level 2 | U.S. treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Debt Securities, Amortized Cost Basis 22,516 15,988
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax (19) (21)
Short-term investments 22,497 15,967
Level 2 | Corporate securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Debt Securities, Amortized Cost Basis 7,353 23,679
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax (12) (40)
Short-term investments 7,341 23,639
Level 2 | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Debt Securities, Amortized Cost Basis 12,570 6,987
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax 0 0
Short-term investments $ 12,570 $ 6,987