Organization and Significant Accounting Policies - Excess and Obsolete Inventory Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Excess and Obsolete Inventory Reserve [Roll Forward]
Excess and obsolete inventory reserve, beginning balance	$ 1,131	$ 1,053	$ 825
Provision charged to expense	0	78	228
Write-offs / Recoveries	(131)	0	0
Excess and obsolete inventory reserve, ending balance	$ 1,000	$ 1,131	$ 1,053