Nature of Business and Summary of Significant Accounting Policies Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	$ 61	$ 21	$ 34
Write-offs	(6)	0	(11)
Change in provision	(10)	40	(2)
Balance at end of year	$ 45	$ 61	$ 21