Unaudited Quarterly Financial Data (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	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 4,912	$ 6,452	$ 8,948	$ 10,155	$ 15,827	$ 16,070	$ 11,847	$ 12,791	$ 30,467	$ 56,535	$ 45,166
Cost of sales	4,883	3,563	5,050	6,141	9,926	10,654	8,125	7,766	19,637	36,471	27,144
Net (loss) from continuing operations	(4,340)	(1,296)	(936)	(1,279)	900	1,055	(1,679)	(191)	(7,851)	85	(6,535)
Income (loss) from discontinued operations	0	18	(9)	(10)	(4)	(10)	(74)	(25)	(1)	(113)	(3,914)
Net loss	$ (4,340)	$ (1,278)	$ (945)	$ (1,289)	$ 896	$ 1,045	$ (1,753)	$ (216)	$ (7,852)	$ (28)	$ (10,449)
Basic net loss per common share
Continuing operations (in dollars per share)	$ (0.18)	$ (0.05)	$ (0.04)	$ (0.05)	$ 0.04	$ 0.04	$ (0.07)	$ (0.01)	$ (0.32)	$ 0.00	$ (0.28)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	(0.16)
Basic (in dollars per share)	(0.18)	(0.05)	(0.04)	(0.05)	0.04	0.04	(0.07)	(0.01)	(0.32)	0.00	(0.44)
Diluted net loss per common share
Continuing operations (in dollars per share)	(0.18)	(0.05)	(0.04)	(0.05)	0.04	0.04	(0.07)	(0.01)	(0.32)	0.00	(0.28)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	(0.16)
Diluted (in dollars per share)	$ (0.18)	$ (0.05)	$ (0.04)	$ (0.05)	$ 0.04	$ 0.04	$ (0.07)	$ (0.01)	$ (0.32)	$ 0.00	$ (0.44)