Nature of Business and Summary of Significant Accounting Policies Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	$ 45	$ 61	$ 21
Write-offs	(28)	(6)	0
Change in provision	25	(10)	40
Balance at end of year	$ 42	$ 45	$ 61