Convertible Preferred Stock And Stockholders' Equity (Summary Of Reserved Shares Of Common Stock) (Details) - shares	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved shares of common stock	92,322,345	88,525,291
Series A Convertible Preferred Stock Series [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved shares of common stock	47,844,562	47,844,562
Warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved shares of common stock	38,779,119	38,963,443
Stock Award Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved shares of common stock	5,573,046	1,524,996
2009 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved shares of common stock	125,618	192,290