Basis of Presentation and Significant Accounting Policies - Reserves For Excess And Obsolete Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reserve For Excess and Obsolete Inventories
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 380	$ 453
Provision adjustment	50	42
Write-offs and scrap	(47)	(115)
Ending balance	$ 383	380
Inventory Sold During Year
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Write-offs and scrap		$ (90)