Accounts Receivable (Allowance) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of period	$ 90	$ 115
Provisions for losses on accounts receivables, net of recoveries	(184)	(123)
Accounts receivable written off, net of recoveries	0	0
Balance, end of period	$ 274	$ 238