Discontinued Operations - Disposal Groups, Including Discontinued Operations (Details) - USD ($) $ in Thousands		3 Months Ended							12 Months Ended
	Jun. 07, 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
Discontinued Operations And Disposal Groups [Abstract]
Service revenue									$ 1,165	$ 1,462	$ 1,254
Product sales									4,233	5,708	10,736
Total revenue									5,398	7,170	11,990
Cost of services, exclusive of depreciation expense shown below									690	1,163	709
Cost of product sales, exclusive of depreciation expense shown below									3,196	5,696	8,573
Depreciation and amortization										115	416
Other expense (income)									91	72	(180)
Operating income									1,421	124	2,472
Gain on sale	$ 8,300								8,319
Income from discontinued operations before income tax expense									9,740	124	2,472
Income tax expense									1,907	182	361
Income (loss) from discontinued operations, net of income taxes		$ (397)	$ 7,971	$ 259	$ 408	$ 208	$ (328)	$ (346)	$ 7,833	(58)	$ 2,111
Current assets					3,712					3,712
Non-current assets					1,848					1,848
Total assets					5,560					5,560
Current liabilities					1,633					1,633
Non-current liabilities					82					82
Total liabilities					$ 1,715					$ 1,715