Business Segments - Summary of company's operations (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 10,915,000			$ 10,297,000			$ 30,003,000	$ 39,249,000
Costs of goods sold, inclusive of depreciation and amortization	(9,143,000)			(10,462,000)			(25,366,000)	(31,682,000)
Gross margin (loss)	1,772,000			(165,000)			4,637,000	7,567,000
Selling, general and administrative	(2,721,000)			(2,096,000)			(6,903,000)	(6,112,000)
Litigation Settlement, Expense	1,890,000						1,890,000
Total operating costs and expenses	4,611,000			2,096,000			8,793,000	6,112,000
Operating (loss)/income	(2,839,000)			(2,261,000)			(4,156,000)	1,455,000
Other income: employee retention credit (ERC)	1,978,000						5,622,000
Gain On Paycheck Protection Program Loan Forgiveness	4,000,000						4,000,000
Interest expense	(5,000)			(42,000)			(132,000)	(134,000)
Total other income/(expense)	5,973,000			(42,000)			9,490,000	(134,000)
Income (loss) before income tax provision	3,134,000			(2,303,000)			5,334,000	1,321,000
Income tax (benefit)/ provision	(104,000)			(521,000)			369,000	240,000
Net income/(loss)	3,238,000	$ 1,186,000	$ 541,000	(1,782,000)	$ 965,000	$ 1,898,000	4,965,000	1,081,000
Total Assets	54,213,000						54,213,000		$ 50,328,000
Capital expenditures							68,000	708,000
Operating Segments
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	10,915,000			10,297,000			30,003,000	39,249,000
Costs of goods sold, inclusive of depreciation and amortization	(9,143,000)			(10,462,000)			(25,366,000)	(31,682,000)
Gross margin (loss)	$ 1,772,000			$ (165,000)			$ 4,637,000	$ 7,567,000
Gross margin %	16.20%			(1.60%)			15.50%	19.30%
Selling, general and administrative	$ (2,721,000)			$ (2,096,000)			$ (6,903,000)	$ (6,112,000)
Litigation Settlement, Expense	(1,890,000)						(1,890,000)
Total operating costs and expenses	13,754,000			12,558,000			(34,159,000)	(37,794,000)
Operating (loss)/income	(2,839,000)			(2,261,000)			(4,156,000)	1,455,000
Other income: employee retention credit (ERC)	1,978,000						5,622,000
Gain On Paycheck Protection Program Loan Forgiveness	4,000,000						4,000,000
Interest expense	(5,000)			(42,000)			(132,000)	(134,000)
Total other income/(expense)	5,973,000			(42,000)			9,490,000	(134,000)
Income (loss) before income tax provision	3,134,000			(2,303,000)			5,334,000	1,321,000
Income tax (benefit)/ provision	(104,000)			(521,000)			369,000	240,000
Net income/(loss)	3,238,000			(1,782,000)			4,965,000	1,081,000
Total Assets	54,213,000						54,213,000		50,328,000
Capital expenditures	55,000			115,000			68,000	708,000
Operating Segments | ATG
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	8,449,000			8,184,000			23,495,000	33,228,000
Costs of goods sold, inclusive of depreciation and amortization	(6,762,000)			(8,635,000)			(19,214,000)	(26,495,000)
Gross margin (loss)	$ 1,687,000			$ (451,000)			$ 4,281,000	$ 6,733,000
Gross margin %	20.00%			(5.50%)			18.20%	20.30%
Selling, general and administrative	$ (2,240,000)			$ (1,712,000)			$ (5,586,000)	$ (4,857,000)
Litigation Settlement, Expense	(1,800,000)						(1,800,000)
Total operating costs and expenses	10,802,000			10,347,000			(26,600,000)	(31,352,000)
Operating (loss)/income	(2,353,000)			(2,163,000)			(3,105,000)	1,876,000
Other income: employee retention credit (ERC)	1,598,000						4,584,000
Gain On Paycheck Protection Program Loan Forgiveness	4,000,000						4,000,000
Interest expense	(5,000)			(41,000)			(130,000)	(125,000)
Total other income/(expense)	5,593,000			(41,000)			8,454,000	(125,000)
Income (loss) before income tax provision	3,240,000			(2,204,000)			5,349,000	1,751,000
Income tax (benefit)/ provision	(83,000)			(512,000)			370,000	318,000
Net income/(loss)	3,323,000			(1,692,000)			4,979,000	1,433,000
Total Assets	44,784,000						44,784,000		40,826,000
Capital expenditures	54,000			99,000			64,000	640,000
Operating Segments | CPG
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	2,466,000			2,113,000			6,508,000	6,021,000
Costs of goods sold, inclusive of depreciation and amortization	(2,381,000)			(1,827,000)			(6,152,000)	(5,187,000)
Gross margin (loss)	$ 85,000			$ 286,000			$ 356,000	$ 834,000
Gross margin %	3.40%			13.50%			5.50%	13.90%
Selling, general and administrative	$ (481,000)			$ (384,000)			$ (1,317,000)	$ (1,255,000)
Litigation Settlement, Expense	(90,000)						(90,000)
Total operating costs and expenses	2,952,000			2,211,000			(7,559,000)	(6,442,000)
Operating (loss)/income	(486,000)			(98,000)			(1,051,000)	(421,000)
Other income: employee retention credit (ERC)	380,000						1,038,000
Interest expense				(1,000)			(2,000)	(9,000)
Total other income/(expense)	380,000			(1,000)			1,036,000	(9,000)
Income (loss) before income tax provision	(106,000)			(99,000)			(15,000)	(430,000)
Income tax (benefit)/ provision	(21,000)			(9,000)			(1,000)	(78,000)
Net income/(loss)	(85,000)			(90,000)			(14,000)	(352,000)
Total Assets	9,429,000						9,429,000		$ 9,502,000
Capital expenditures	$ 1,000			$ 16,000			$ 4,000	$ 68,000