Business Segments and Significant Customers (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 item	Mar. 31, 2014
Business Segments, Concentration of Credit Risk and Significant Customers
Number of business segments	1
Number of measurements of profitability	1
Business Segments
Total net revenue	$ 776	$ 1,332
Taiwan
Business Segments
Total net revenue	479	337
North America
Business Segments
Total net revenue	177	350
Japan
Business Segments
Total net revenue	112	623
Rest of world
Business Segments
Total net revenue	8	11
Europe
Business Segments
Total net revenue		$ 11