STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2013 ESPP	Sep. 30, 2014 ESPP period	Sep. 30, 2013 ESPP	Nov. 09, 2010 ESPP	Sep. 30, 2014 ESPP Maximum	Sep. 30, 2014 ESPP Maximum	Sep. 30, 2014 2009 Equity Incentive Plan	Sep. 30, 2014 Employee stock option	Sep. 30, 2014 Employee stock option	Dec. 31, 2013 Employee stock option	Sep. 30, 2014 Employee stock option Maximum	Sep. 30, 2014 Restricted common stock	Sep. 30, 2014 Restricted common stock Maximum
Stock-based compensation
Number of shares reserved for issuance											6,200,000
Vesting period													3 years
Expiration period													10 years
Number of shares available for grant or purchase						479,341					1,985,415
Number of Shares
Outstanding at the beginning of the period (in shares)													3,771,305
Options granted (in shares)													1,000,000
Cancelled/forfeited (in shares)													(1,365,916)
Outstanding at the end of the period (in shares)												3,405,389	3,405,389	3,771,305
Vested and exercisable at the end of the period (in shares)												1,946,639	1,946,639
Vested and exercisable at the end of the period and expected to vest thereafter (in shares)												3,335,103	3,335,103
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)													$ 9.13
Options granted (in dollars per share)													$ 1.59
Canceled/forfeited (in dollars per share)													$ 8.60
Outstanding at the end of the period (in dollars per share)												$ 7.13	$ 7.13	$ 9.13
Vested and exercisable at the end of the period (in dollars per share)												$ 10.92	$ 10.92
Vested and exercisable at the end of the period and expected to vest thereafter (in dollars per share)												$ 7.25	$ 7.25
Weighted-Average Remaining Contractual Term (in years)
Outstanding at the end of the period													6 years 11 months 9 days	6 years 8 months 16 days
Vested and exercisable at the end of the period													5 years 4 months 21 days
Vested and exercisable at the end of the period and expected to vest thereafter													6 years 10 months 21 days
Weighted-Average Grant-Date Fair Value
Outstanding at the beginning of the period (in dollars per share)													$ 3.87
Options granted (in dollars per share)												$ 0.90
Canceled/forfeited (in dollars per share)													$ 3.69
Outstanding at the end of the period (in dollars per share)												$ 3.06	$ 3.06	$ 3.87
Vested and exercisable at the end of the period (in dollars per share)												$ 4.47	$ 4.47
Vested and exercisable at the end of the period and expected to vest thereafter (in dollars per share)												$ 3.11	$ 3.11
Aggregate Intrinsic Value
Outstanding														$ (28,964)
Vested and exercisable at the end of the period												(18,435)	(18,435)
Vested and exercisable at the end of the period and expected to vest thereafter												(19,344)	(19,344)
Stock-based compensation, additional disclosure
Closing stock price (in dollars per share)	$ 1.45		$ 1.45
Number of units
Unvested at the beginning of the period (in shares)																114,667
Granted (in shares)																276,069
Vested (in shares)																(254,025)
Cancelled (in shares)																(24,635)
Unvested at the end of the period (in shares)																112,076
Expected to vest at the end of the period (in shares)																112,076
Weighted-Average Grant-Date Fair Value
Unvested at the beginning of the period (in dollars per share)																$ 4.32
Granted (in dollars per share)																$ 1.58
Vested (in dollars per share)																$ 2.71
Unvested at the end of the period (in dollars per share)																$ 8.11
Expected to vest at the end of the period (in dollars per share)																$ 8.11
Unrecognized compensation cost
Unrecognized compensation cost												1,129	1,129			193
Weighted-average remaining vesting period of recognition															1 year		1 year
Stock-based compensation plans
Shares reserved for issuance under stock purchase plan								500,000
Discount rate (as a percent)						10.00%
Number of Offering periods						4
Stock-based compensation expense	$ 322	$ 563	$ 1,023	$ 1,677	$ 0		$ 1		$ 1	$ 1
Assumptions used to estimate the fair values of the stock options granted
Weighted-average estimated fair value of options granted during the period (in dollars per share)												$ 0.90