Accounts Receivable (Allowance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts:
Balance, beginning of period	$ 264	$ 119	$ 90
Provision for losses on accounts receivable, net of adjustments	91	174	179
Accounts receivable written off, net of recoveries	(2)	(29)	(150)
Balance, end of period	$ 353	$ 264	$ 119