INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2017

INCOME TAXES

Schedule of significant components of net deferred tax assets

	December 31,
	2017		2016
Net operating loss carryforward	$	31,533	$	37,245
Research and development credit carryforward		1,173		1,065
Stock-based compensation		2,828		5,235
Depreciation and amortization		71		31
Accrued expenses		357		264
Charitable contributions		27		63
Subtotal		35,989		43,903
Valuation allowance		(35,989)		(43,903)
Net deferred taxes	$	—	$	—

Schedule of income tax benefits computed using the federal statutory income tax rate

	December 31,
	2017		2016		2015
Statutory rate	(34.0)	%	(34.0)	%	(34.0)	%
State taxes, net of benefit	(4.7)	%	(5.4)	%	(3.5)	%
Permanent differences:
Derivative losses	2.9	%	(0.9)	%	11.0	%
Other	1.1	%	0.2	%	0.3	%
Research and development tax credit	(0.2)	%	(0.5)	%	(0.4)	%
Other	1.4	%	0.5	%	0.4	%
Adoption of ASU 2016-09	7.4	%	—	%	—	%
Increase / (decrease) in valuation reserve	(32.0)	%	40.1	%	26.2	%
Change in federal tax rate	58.1	%	—	%	—	%
Effective tax rate	0.0	%	0.0	%	0.0	%