STOCK OPTIONS (Tables)

12 Months Ended

Dec. 31, 2017

STOCK OPTIONS.

Schedule of assumptions used principally in determining the fair value of options granted

	December 31,
	2017	2016	2015
Risk-free interest rate	1.69 - 2.36%	1.20 - 1.52%	1.53 - 1.89%
Expected dividend yield	0%	0%	0%
Expected term (employee grants)	6.22 Years	5.99 years	6.00 years
Expected volatility	104%	111%	116%

Summary of option activity

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
Options	Shares	Price		Term in Years	Value
Outstanding at December 31, 2016	3,193,785	$	7.52
Granted	1,439,463	$	3.94
Forfeited	(1,174,616)	$	6.40
Exercised	(89,387)	$	0.29
Outstanding at December 31, 2017	3,369,245	$	6.57	7.14	$	22
Vested at December 31, 2017	2,224,246	$	7.54	6.22	$	22
Vested and expected to vest at December 31, 2017	3,369,245	$	6.57	7.14	$	22

Summary of restricted stock unit activity

			Weighted-Average
	Number of Grants		Grant Date Fair Value
Unvested balance at December 31, 2016	—	$	—
Granted	595,000		1.06
Vested	—		—
Forfeited	(95,000)		1.25
Unvested balance at December 31, 2017	500,000	$	1.03