Detail of Selected Balance Sheet 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	$ 182	$ 172	$ 151
Bad debt expense	119	73	68
Write-offs, net of recoveries	(90)	(63)	(47)
Balance at end of year	$ 211	$ 182	$ 172