STOCK-BASED COMPENSATION (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2014
The 2004 Plan
Stock-based compensation
Number Outstanding (in shares)	6,002,334
Weighted-Average Remaining Contractual Term	9 years 7 months 10 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 7.84
Number Exercisable (in shares)	3,491,018
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 6.76
The 2004 Plan | $1.49-$5.35
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 1.49
Range of Exercise Prices, high end of range (in dollars per share)	$ 5.35
Number Outstanding (in shares)	860,494
Weighted-Average Remaining Contractual Term	5 years 26 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 3.95
Number Exercisable (in shares)	759,278
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 3.77
The 2004 Plan | $5.56-$5.91
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 5.56
Range of Exercise Prices, high end of range (in dollars per share)	$ 5.91
Number Outstanding (in shares)	690,578
Weighted-Average Remaining Contractual Term	7 years 4 months 6 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 5.78
Number Exercisable (in shares)	441,736
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 5.75
The 2004 Plan | $5.94-$6.11
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 5.94
Range of Exercise Prices, high end of range (in dollars per share)	$ 6.11
Number Outstanding (in shares)	702,771
Weighted-Average Remaining Contractual Term	6 years 10 months 2 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 6.06
Number Exercisable (in shares)	472,510
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 6.06
The 2004 Plan | $6.14-$6.29
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 6.14
Range of Exercise Prices, high end of range (in dollars per share)	$ 6.29
Number Outstanding (in shares)	145,741
Weighted-Average Remaining Contractual Term	4 years 8 months 5 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 6.21
Number Exercisable (in shares)	101,679
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 6.24
The 2004 Plan | $6.77-$6.77
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 6.77
Range of Exercise Prices, high end of range (in dollars per share)	$ 6.77
Number Outstanding (in shares)	893,078
Weighted-Average Remaining Contractual Term	7 years 9 months 4 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 6.77
Number Exercisable (in shares)	380,299
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 6.77
The 2004 Plan | $7.02-$8.36
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 7.02
Range of Exercise Prices, high end of range (in dollars per share)	$ 8.36
Number Outstanding (in shares)	764,825
Weighted-Average Remaining Contractual Term	6 years 7 months 13 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 7.88
Number Exercisable (in shares)	631,493
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 7.95
The 2004 Plan | $8.45-$8.71
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 8.45
Range of Exercise Prices, high end of range (in dollars per share)	$ 8.71
Number Outstanding (in shares)	518,058
Weighted-Average Remaining Contractual Term	6 years 3 months 4 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 8.53
Number Exercisable (in shares)	438,430
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 8.52
The 2004 Plan | $9.02-$9.02
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 9.02
Range of Exercise Prices, high end of range (in dollars per share)	$ 9.02
Number Outstanding (in shares)	2,187
Weighted-Average Remaining Contractual Term	6 years 2 months 19 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 9.02
Number Exercisable (in shares)	1,875
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 9.02
The 2004 Plan | $12.05-$12.05
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 12.05
Range of Exercise Prices, high end of range (in dollars per share)	$ 12.05
Number Outstanding (in shares)	97,000
Weighted-Average Remaining Contractual Term	8 years 10 months 24 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 12.05
Number Exercisable (in shares)	1,146
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 12.05
The 2004 Plan | $12.69-$12.69
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 12.69
Range of Exercise Prices, high end of range (in dollars per share)	$ 12.69
Number Outstanding (in shares)	1,327,602
Weighted-Average Remaining Contractual Term	8 years 9 months 22 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 12.69
Number Exercisable (in shares)	262,572
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 12.69
The 2014 Plan
Stock-based compensation
Number Outstanding (in shares)	745,672
Weighted-Average Remaining Contractual Term	9 years 7 months 10 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 13.42
Number Exercisable (in shares)	10,167
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 11.80
The 2014 Plan | $10.80-$10.80
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 10.80
Range of Exercise Prices, high end of range (in dollars per share)	$ 10.80
Number Outstanding (in shares)	82,000
Weighted-Average Remaining Contractual Term	9 years 6 months 29 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 10.80
The 2014 Plan | $10.86-$10.86
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 10.86
Range of Exercise Prices, high end of range (in dollars per share)	$ 10.86
Number Outstanding (in shares)	107,960
Weighted-Average Remaining Contractual Term	9 years 2 months 16 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 10.86
The 2014 Plan | $11.11-$11.11
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 11.11
Range of Exercise Prices, high end of range (in dollars per share)	$ 11.11
Number Outstanding (in shares)	10,000
Weighted-Average Remaining Contractual Term	9 years 4 months 21 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 11.11
Number Exercisable (in shares)	8,333
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 11.11
The 2014 Plan | $11.83-$11.83
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 11.83
Range of Exercise Prices, high end of range (in dollars per share)	$ 11.83
Number Outstanding (in shares)	150,000
Weighted-Average Remaining Contractual Term	9 years 6 months 15 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 11.83
The 2014 Plan | $11.84-$11.84
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 11.84
Range of Exercise Prices, high end of range (in dollars per share)	$ 11.84
Number Outstanding (in shares)	7,000
Weighted-Average Remaining Contractual Term	9 years 4 months 28 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 11.84
The 2014 Plan | $14.94-$14.94
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 14.94
Range of Exercise Prices, high end of range (in dollars per share)	$ 14.94
Number Outstanding (in shares)	22,000
Weighted-Average Remaining Contractual Term	9 years 7 months 17 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 14.94
Number Exercisable (in shares)	1,834
Weighted-Average Exercise Price (Exercisable) (in dollars per share)	$ 14.94
The 2014 Plan | $15.02-$15.02
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 15.02
Range of Exercise Prices, high end of range (in dollars per share)	$ 15.02
Number Outstanding (in shares)	63,300
Weighted-Average Remaining Contractual Term	9 years 8 months 23 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 15.02
The 2014 Plan | $15.31-$15.31
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 15.31
Range of Exercise Prices, high end of range (in dollars per share)	$ 15.31
Number Outstanding (in shares)	150,000
Weighted-Average Remaining Contractual Term	9 years 8 months 1 day
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 15.31
The 2014 Plan | $15.53-$15.53
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 15.53
Range of Exercise Prices, high end of range (in dollars per share)	$ 15.53
Number Outstanding (in shares)	59,112
Weighted-Average Remaining Contractual Term	9 years 11 months 1 day
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 15.53
The 2014 Plan | $15.74-$15.74
Stock-based compensation
Range of Exercise Prices, low end of range (in dollars per share)	$ 15.74
Range of Exercise Prices, high end of range (in dollars per share)	$ 15.74
Number Outstanding (in shares)	94,300
Weighted-Average Remaining Contractual Term	9 years 10 months 24 days
Weighted-Average Exercise Price (Outstanding) (in dollars per share)	$ 15.74