Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v2.4.0.6
Fair Value Measurements (Details) (USD $)
Mar. 31, 2013
Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available-for-sale Securities $ 92,000 $ 92,000
Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 53,333,000  
Marketable Securities, Fair Value Disclosure 3,788,000  
Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 53,333,000  
Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 53,333,000  
Marketable Securities, Fair Value Disclosure 3,788,000  
Money Market Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 48,000  
Money Market Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 48,000  
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 48,000  
Mutual Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 44,000  
Mutual Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 44,000  
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 44,000  
US Treasury Securities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 2,434,000  
US Treasury Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 2,434,000  
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 2,434,000  
US Government Agencies Securities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 1,262,000  
US Government Agencies Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 1,262,000  
US Government Agencies Securities [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Marketable Securities, Fair Value Disclosure 1,262,000  
Cash [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 11,505,000  
Cash [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 11,505,000  
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 11,505,000  
Money Market Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 41,828,000  
Money Market Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure 41,828,000  
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and Cash Equivalents, Fair Value Disclosure $ 41,828,000