Summary of Significant Accounting Policies Warranty Reserve (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 1,000	$ 0
Provisions	331,000	18,000
Warranty expenses incurred	(140,000)	(17,000)
Ending balance	$ 192,000	$ 1,000