INCOME TAXES, Reconciliation of Effective Income Tax Rate and Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the effective income tax rate to the federal statutory rate [Abstract]
Federal statutory rate	34.00%	34.00%
State income taxes	(1.34%)	4.94%
Change in valuation allowance relating to operations	(42.38%)	(22.34%)
Impact of federal tax rate decrease	(6.44%)	0.00%
Impact of federal statutory rate change on valuation allowance	13.74%	0.00%
Foreign tax rate differential	(2.20%)	0.00%
Nondeductible expenses	(1.93%)	8.92%
Minimum tax credit refundable	3.51%	0.00%
Total	(3.04%)	25.52%
Increase (decrease) in deferred tax assets	$ (4,245)
Increase (decrease) in valuation allowance	(3,937)
Deferred Tax Assets [Abstract]
Net operating loss carryforwards			$ 10,623	$ 14,106
Amortization			262	282
Stock-based compensation			49	73
Allowance for doubtful accounts			36	76
Reserve for obsolete inventory			235	351
Tax credits			438	557
Expense accruals			579	392
Deferred revenue			893	1,523
Total gross deferred taxes			13,115	17,360
Valuation allowance	(15,695)	$ (15,695)	(11,758)	(15,695)
Net deferred tax assets			1,357	1,665
Deferred Tax Liabilities [Abstract]
Deferred commissions			(224)	(337)
Goodwill			(668)	(607)
Differences in timing of revenue recognition			(112)	(112)
Depreciation			(573)	(613)
Total deferred tax liabilities			(1,577)	(1,669)
Total deferred tax assets (liabilities)			(220)	(4)
Recorded as [Abstract]
Non-current deferred tax assets (in other assets)			0	108
Non-current deferred tax liabilities			(220)	(112)
Total deferred tax assets (liabilities)			(220)	$ (4)
Valuation allowance [Roll Forward]
Valuation allowance, beginning of period	15,695	16,170
Partial release of allowance	0	0
Change in valuation allowance	(3,937)	(475)
Valuation allowance, end of period	$ 11,758	$ 15,695
Federal and State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards			$ 39,000
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration date	Dec. 31, 2020
Maximum [Member]
Reconciliation of the effective income tax rate to the federal statutory rate [Abstract]
Federal statutory rate	35.00%
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards expiration date	Dec. 31, 2037