SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Share-Based Compensation Expense

The following table sets forth the amount of share-based compensation expense recognized by the Company by line item on its consolidated statements of operations for the years ended December 31, 2019, 2018 and 2017 (in thousands):

	Year ended December 31,
	2019		2018		2017
Research and development	$	188	$	505	$	404
General and administrative	1,049		778		977
Total Share-based Compensation	$	1,237	$	1,283	$	1,381

Schedule of Stock Option Activity

The following table sets forth a summary of the Company’s total stock option activity, including awards granted under the 2014 Plan and 2009 Plan and inducement grants made outside of stockholder approved plans, for the years ended December 31, 2019, 2018 and 2017:

	Number of Shares under Option (in thousands)		Weighted-Average Exercise Price per Option	Weighted-Average Remaining Contractual  Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2016	2,024		$4.41	8.73	$	841
Granted	1,303		$1.64
Exercised	(140	)	$0.28
Canceled or forfeited	(491	)	$5.10
Outstanding at December 31, 2017	2,696		$3.16	8.55	$	146
Granted	3,546		$1.71
Exercised	(439	)	$0.62
Canceled or forfeited	(1,861	)	$3.21
Outstanding at December 31, 2018	3,942		$2.12	9.14	$	57
Granted	3,986		$1.02
Exercised	(90	)	$1.10
Canceled or forfeited	(1,602	)	$1.78
Outstanding at December 31, 2019	6,236		$1.52	8.83	$	358
Exercisable at December 31, 2019	1,866		$2.31	8.06	$	62

Schedule of Weighted-Average Inputs and Assumptions in Black-Scholes Option

For the years ended December 31, 2019, 2018 and 2017, the grant-date fair value of stock options was determined using the following weighted-average inputs and assumptions in the Black-Scholes option pricing model:

	Year ended December 31,
	2019	2018	2017
Fair value of common stock	$1.02	$1.71	$1.74
Exercise price of the option	$1.02	$1.71	$1.74
Expected term (years)	5.98	5.97	5.59
Risk-free interest rate	2.1%	2.8%	1.9%
Expected volatility	78.1%	74.2%	81.6%
Dividend yield	—%	—%	—%

Summary of Status and Changes of Unvested Restricted Stock

The following table sets forth a summary of the Company's restricted stock activity for the years ended December 31, 2018 and 2017:

	Non-vested Restricted Stock Awards (in thousands)		Weighted-Average Grant Date Fair Value	Non-vested Restricted Stock Units (in thousands)		Weighted-Average Grant Date Fair Value
Non-vested at December 31, 2016	22		$11.43	3		$4.09
Vested	(18	)	$11.43	(3	)	$4.09
Non-vested at December 31, 2017	4		$11.43	—
Vested	(4	)	$11.43
Non-vested at December 31, 2018	—