Organization and Summary of Significant Accounting Policies (Details) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2011
Organization and Summary of Significant Accounting Policies (Textual) [Abstract]          
Cash cash equivalents and marketable securities $ 98,700,000   $ 98,700,000    
Working Capital 97,900,000   97,900,000    
Accumulated deficit (105,556,000)   (105,556,000)   (100,094,000)
Employee stock based compensation costs 707,000 465,000 2,005,000 1,594,000  
Shares of common stock issued 26,233   171,212    
Stock option modification expense   197,000 28,000 154,000  
Non-employee stock based compensation 33,000 16,000 166,000 92,000  
Tax benefits of stock based compensation costs recognized