INCOME TAXES - Reconciliation of Expected Provision for Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of expected provision for income taxes, computed by applying the U.S. federal income tax rate to income before taxes, to income tax expense
U.S. federal income tax rate (as a percent)	34.00%	34.00%
Expected provision for federal income taxes	$ (23,000)	$ 77,000
State income taxes, net of federal benefit	7,000	7,000
Domestic manufacturers deduction		(6,000)
Non-deductible meals, entertainment, and life insurance	27,000	29,000
Research and development credit	(32,000)	(30,000)
Change in valuation allowance	15,000	15,000
Other	2,000	(2,000)
Income tax expense	(4,000)	90,000
Deferred tax liabilities:
Accrued vacation	32,000	26,000
Inventories reserve	66,000	126,000
Allowance for doubtful accounts	4,000	5,000
Allowance for sales returns	15,000	37,000
Research and development credit carryforward	77,000	45,000
Accrued self-insured medical	3,000	1,000
Property and equipment	(499,000)	(494,000)
Intangible assets	(92,000)	(86,000)
Net operating loss	3,000
Other	5,000
Valuation allowance	(60,000)	(45,000)
Net deferred tax liabilities	$ (446,000)	$ (385,000)