Balance Sheet Components (Accrued Liabilities) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
Balance Sheet Components [Abstract]    
Accrued clinical trials $ 455 $ 417
Accrued compensation 289 1,093
Accrued consulting 237 315
Other accrued liabilities 24 77
Accrued liabilities $ 1,005 $ 1,902