Quarterly Financial Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Interim Period, Costs Not Allocable [Line Items]
Sales									$ 157,893	$ 153,029
Operating expenses (a)	$ 19,195	$ 18,317	$ 18,381	$ 18,953	$ 16,623	$ 17,269	$ 16,887	$ 17,944
Loss from continuing operations (a)	(3,325)	(4,858)	(6,679)	(6,234)	(2,377)	(1,857)	(2,580)	(3,832)	(21,096)	(10,646)
Net loss from continuing operations (a)	(2,910)	(3,308)	(3,294)	(6,497)	(2,665)	(1,931)	(2,402)	(4,446)	(16,009)	(11,444)
Income from discontinued operations, net of tax	(573)	(1,036)	50,630	243	843	757	1,059	553	49,264	3,212
Net loss	$ (3,483)	$ (4,344)	$ 47,336	$ (6,254)	$ (1,822)	$ (1,174)	$ (1,343)	$ (3,893)	$ 33,255	$ (8,232)
Net loss continuing operations per share
Basic (in USD per share)	$ (0.17)	$ (0.19)	$ (0.19)	$ (0.38)	$ (0.15)	$ (0.11)	$ (0.14)	$ (0.27)
Diluted (in USD per share)	(0.17)	(0.19)	(0.19)	(0.38)	(0.15)	(0.11)	(0.14)	(0.27)
Net income (loss) discontinued operations pre share
Basic (in USD per share)	(0.03)	(0.06)	2.90	0.01	0.05	0.04	0.06	0.03
Diluted (in USD per share)	(0.03)	(0.06)	2.90	0.01	0.05	0.04	0.06	0.03
Net (loss) income per share:
Basic (in dollars per share)	(0.20)	(0.25)	2.71	(0.36)	(0.11)	(0.07)	(0.08)	(0.23)
Diluted (in dollars per share)	$ (0.20)	$ (0.25)	$ 2.71	$ (0.36)	$ (0.11)	$ (0.07)	$ (0.08)	$ (0.23)
Product
Interim Period, Costs Not Allocable [Line Items]
Sales	$ 18,713	$ 14,808	$ 15,189	$ 13,215	$ 16,756	$ 16,367	$ 16,162	$ 13,992
Cost of product and service sales	11,131	10,823	12,649	8,284	10,726	9,767	10,094	8,923
Service
Interim Period, Costs Not Allocable [Line Items]
Sales	23,763	24,503	24,541	23,161	22,924	22,945	22,470	21,413
Cost of product and service sales	$ 15,475	$ 15,029	$ 15,379	$ 15,373	$ 14,708	$ 14,133	$ 14,231	$ 12,370