Organization and Summary of Significant Accounting Policies - Product Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Product Warranties Disclosures [Abstract]
Product warranty	Our products are sold with a limited warranty for a period of one year, warranting that the product conforms to specifications and is free from material defects in design, materials and workmanship.
Product warranty period	1 year
Product warranty claim recorded	$ 27	$ 250
Product warranty claim incurred	185		$ 41
Product warranty accrual	$ 51		$ 209