Balance Sheet Detail Deferred Service Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Movement in Deferred Revenue [Roll Forward]
Deferred Revenue	$ 4,011	$ 5,233
Gross Billings	3,891	3,244
Deferred Revenue, Revenue Recognized	(4,060)	(4,466)
Deferred Revenue	3,842	4,011
Deferred Service Revenue, Current	2,697	3,962
Deferred Revenue, Noncurrent	$ 1,145	$ 49