Stockholders' Equity (Details 2) (USD $)
In Thousands, except Share data, unless otherwise specified
 1 Months Ended 6 Months Ended
Jan. 31, 2012
Jun. 30, 2012
Jun. 30, 2012
Stock Options
Jun. 30, 2011
Stock Options
Jun. 30, 2012
Stock Options
Minimum
Jun. 30, 2012
Stock Options
Maximum
Jun. 30, 2012
Stock Options
Directors
Jun. 30, 2012
Restricted Stock
Jun. 30, 2011
Restricted Stock
Stock Options                  
Number of additional shares authorized under the plan 737,429                
Number of shares authorized under the plan   2,975,385              
Number of shares available for future grants under the plan   559,892              
Number of Shares                  
Outstanding at the beginning of the period (in shares)     1,784,285            
Granted (in shares)     714,630       83,042    
Exercised (in shares)     (6,237)            
Cancelled/forfeited (in shares)     (184,388)            
Outstanding at the end of the period (in shares)     2,308,290            
Vested and expected to vest at the end of the period (in shares)     2,197,952            
Exercisable at the end of the period (in shares)     1,199,334            
Weighted Average Exercise Price                  
Outstanding at the beginning of the period (in dollars per share)     $ 4.31            
Granted (in dollars per share)     $ 3.09            
Exercised (in dollars per share)     $ 1.92            
Cancelled/forfeited (in dollars per share)     $ 8.80            
Outstanding at the end of the period (in dollars per share)     $ 3.58            
Vested and expected to vest at the end of the period (in dollars per share)     $ 3.61            
Exercisable at the end of the period (in dollars per share)     $ 3.03            
Weighted Average Remaining Contractual Term in Years                  
Outstanding at the end of the period     7 years 11 months 12 days            
Vested and expected to vest at the end of the period     7 years 10 months 10 days            
Exercisable at the end of the period     6 years 8 months 26 days            
Aggregate Intrinsic Value                  
Outstanding at the end of the period     $ 3,031            
Vested and expected to vest at the end of the period     2,924            
Exercisable at the end of the period     2,100            
Additional disclosures pertaining to stock options                  
Stock closing price (in dollars per share)     $ 4.03            
Stock-based compensation expense     734 522       16 5
Unrecognized compensation expense related to unvested awards     $ 2,640         $ 88  
Remaining vesting period of awards     3 years         2 years 10 months 24 days  
Weighted-average fair value of stock options granted (in dollars per share)     $ 2.14            
Assumptions Used:                  
Risk free interest rate, low end of range (as a percent)     0.73%            
Risk free interest rate, high end of range (as a percent)     1.18%            
Expected life in Years         5 years 6 years 1 month 6 days      
Expected volatility, low end of range (as a percent)     80.50%            
Expected volatility, high end of range (as a percent)     88.10%            
Dividend Yield (as a percent)     0.00%            
Number of Shares                  
Nonvested shares at the beginning of the period               16,000  
Vested (in shares)               (4,000)  
Nonvested shares at the end of the period               12,000  
Weighted Average Grant Date Fair Value                  
Nonvested shares at the beginning of the period (in dollars per share)               $ 7.73  
Nonvested shares at the end of the period (in dollars per share)               $ 7.73