SEGMENT INFORMATION (Details)	3 Months Ended		9 Months Ended
	Sep. 29, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 29, 2017 USD ($) segment	Sep. 30, 2016 USD ($)	Dec. 30, 2016 USD ($)
SEGMENT INFORMATION
Number of reporting segments | segment			4
Segment reconciliation
Contract revenue	$ 69,007,000	$ 58,660,000	$ 209,191,000	$ 151,516,000
Depreciation and amortization	1,053,000	742,000	2,896,000	2,308,000
Segment profit (loss) before income tax expense	4,178,000	3,010,000	10,678,000	8,720,000
Income tax expense	1,292,000	548,000	1,839,000	1,990,000
Net income (loss)	2,886,000	2,462,000	8,839,000	6,730,000
Segment assets(1)	130,852,000	106,798,000	130,852,000	106,798,000	$ 108,347,000
Intersegment
Segment reconciliation
Contract revenue	0	0	0	0
Reporting Segments | Energy Efficiency Services
Segment reconciliation
Contract revenue	50,031,000	41,988,000	153,877,000	103,574,000
Segment profit (loss) before income tax expense	825,000	1,058,000	3,519,000	4,257,000
Net income (loss)	570,000	895,000	2,913,000	3,285,000
Segment assets(1)	74,955,000	65,383,000	74,955,000	65,383,000
Reporting Segments | Engineering Services
Segment reconciliation
Contract revenue	14,980,000	12,906,000	43,467,000	36,863,000
Segment profit (loss) before income tax expense	2,612,000	1,857,000	6,230,000	4,941,000
Net income (loss)	1,804,000	1,508,000	5,157,000	3,814,000
Segment assets(1)	12,439,000	12,012,000	12,439,000	12,012,000
Reporting Segments | Financial Services
Segment reconciliation
Contract revenue	3,272,000	3,199,000	9,973,000	9,206,000
Segment profit (loss) before income tax expense	244,000	287,000	1,061,000	294,000
Net income (loss)	168,000	221,000	878,000	227,000
Segment assets(1)	6,809,000	5,994,000	6,809,000	5,994,000
Reporting Segments | Homeland Security Services
Segment reconciliation
Contract revenue	724,000	567,000	1,874,000	1,873,000
Segment profit (loss) before income tax expense	(55,000)	4,000	(149,000)	92,000
Net income (loss)	(38,000)	5,000	(124,000)	71,000
Segment assets(1)	799,000	498,000	799,000	498,000
Unallocated Corporate
Segment reconciliation
Segment profit (loss) before income tax expense	552,000	(196,000)	17,000	(864,000)
Net income (loss)	382,000	(167,000)	15,000	(667,000)
Segment assets(1)	58,980,000	46,041,000	58,980,000	46,041,000
Intersegment
Segment reconciliation
Segment assets(1)	$ (23,130,000)	$ (23,130,000)	$ (23,130,000)	$ (23,130,000)