STOCKHOLDERS' EQUTIY AND SHARE-BASED COMPENSATION EXPENSE - Summary of outstanding and exercisable options (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Options Outstanding (in shares)	5,142
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	3 years 10 months 13 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 6.75
Number of Option Exercisable (in shares)	2,979
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 8.36
Range $2.63 - 3.84 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 2.63
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 3.84
Number of Options Outstanding (in shares)	897
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	5 years 0 months 25 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 3.52
Number of Option Exercisable (in shares)	243
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 2.97
Range $3.86 - 4.16 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 3.86
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 4.16
Number of Options Outstanding (in shares)	686
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	5 years 4 months 2 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 3.93
Number of Option Exercisable (in shares)	200
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 3.93
Range $4.21 - 4.44 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 4.21
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 4.44
Number of Options Outstanding (in shares)	629
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	3 years 9 months
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 4.24
Number of Option Exercisable (in shares)	387
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 4.22
Range $4.46 - 5.29 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 4.46
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 5.29
Number of Options Outstanding (in shares)	672
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	4 years 5 months 1 day
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 4.84
Number of Option Exercisable (in shares)	390
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 4.94
Range $5.31 - 6.51 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 5.31
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 6.51
Number of Options Outstanding (in shares)	634
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	4 years 4 months 17 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 5.73
Number of Option Exercisable (in shares)	345
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 5.77
Range $6.57 - 8.29 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 6.57
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 8.29
Number of Options Outstanding (in shares)	709
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	3 years 7 months 27 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 7.54
Number of Option Exercisable (in shares)	500
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 7.75
Range $8.71 - 19.92 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 8.71
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 19.92
Number of Options Outstanding (in shares)	734
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	1 year 0 months 25 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 12.66
Number of Option Exercisable (in shares)	733
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 12.66
Range $21.36 - 37.22 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range Exercise Price, Lower Range Limit (in dollars per share)	$ 21.36
Range of Exercise Price, Upper Range Limit (in dollars per share)	$ 37.22
Number of Options Outstanding (in shares)	181
Options Outstanding, Weighted-Average Remaining Contractual Life (in years)	1 year 0 months 18 days
Option Outstanding, Weighted-Average Exercise Price Per Share (in dollars per share)	$ 25.82
Number of Option Exercisable (in shares)	181
Option Exercisable, Weighted-Average Exercise Price Per Share (in dollars per share)		$ 25.81