Plant Consolidations (Details)		3 Months Ended		6 Months Ended
	Mar. 18, 2015 USD ($) ft²	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) property	Jun. 30, 2015 USD ($)
Restructuring Costs
Restructuring costs		$ 55,000	$ 30,000	$ 178,000	$ 108,000
Total restructuring costs				$ 1,900,000
Number of properties in close proximity to other California operations | property				2
Selling, general, and administrative expenses		6,470,000	6,776,000	$ 12,374,000	12,800,000
Gain on sale fixed assets				(4,000)	(31,000)
Restructuring Charges
Restructuring Costs
Restructuring costs					90,000
Selling, general, and administrative expenses					18,000
Rancho Dominguez, California Facility
Restructuring Costs
Relocation costs			6,000		66,000
Employee severance payments					18,000
Total restructuring costs			6,000		84,000
Newburyport, Massachusetts Facility
Plant Consolidation
Cash charges	$ 2,000,000
Annual cost savings	$ 1,000,000
Restructuring Costs
Acquired commercial building, square foot | ft²	137,000
Restructuring costs	$ 2,100,000
Relocation costs		55,000	24,000	178,000	24,000
Total restructuring costs		$ 55,000	$ 24,000	$ 178,000	$ 24,000
Employee severance payments | Newburyport, Massachusetts Facility
Plant Consolidation
Restructuring charges	180,000
Moving and vacating expenses | Newburyport, Massachusetts Facility
Plant Consolidation
Restructuring charges	1,500,000
Lease Termination | Newburyport, Massachusetts Facility
Plant Consolidation
Restructuring charges	$ 360,000