STOCK-BASED COMPENSATION AND STOCK PLANS (Tables)

6 Months Ended

Jun. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Schedule of stock-based compensation expense

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Research and development	$	109	$	124	$	299	$	396
General and administrative		312		298		716		844
Total stock-based compensation expense	$	421	$	422	$	1,015	$	1,240

Schedule of activity of options under stock plans

Stock Options	Number of Shares			Weighted Average Exercise Price
Outstanding as of December 31, 2015		8,305,950		$	4.24
Granted		1,609,000			1.78
Exercised		(97,498	)		1.16
Cancelled		(628,254	)		5.31
Outstanding as of June 30, 2016		9,189,198		$	3.77
Exercisable as of June 30, 2016		6,103,542		$	4.78

Schedule of shares vested, expected to vest and exercisable

	Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Vested and unvested expected to vest at June 30, 2016		9,020,805	$	3.77		5.8	$	979
Exercisable at June 30, 2016		6,103,542	$	4.78		4.2	$	203

Schedule of restricted stock activity

Restricted Stock	Number of Shares			Weighted Average Grant Date Fair Value
Unvested as of December 31, 2015		58,635		$	2.51
Vested		(29,306	)		2.51
Cancelled		(53	)		2.51
Unvested as of June 30, 2016		29,276		$	2.51