Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Summary of Marketable Securities (Detail)

v2.4.0.8
Fair Value Measurements - Summary of Marketable Securities (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash, amortized cost and estimated fair value $ 10,575 $ 2,440
Restricted cash, amortized cost and estimated fair value 314 314
Money market securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Money market securities, amortized cost and estimated fair value 4,018 15,635
Restricted cash, amortized cost and estimated fair value 314 314
Corporate bonds and commercial paper [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost      
Gross Unrealized Gains      
Gross Unrealized Losses      
Estimated Fair Value      
Total cash and cash equivalents [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost 14,593 18,075
Gross Unrealized Gains      
Gross Unrealized Losses      
Estimated Fair Value 14,593 18,075
U.S government securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost      
Gross Unrealized Gains      
Gross Unrealized Losses      
Estimated Fair Value      
U.S agency securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost      
Gross Unrealized Gains      
Gross Unrealized Losses      
Estimated Fair Value      
Corporate bonds and commercial paper [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost 24,627 57,312
Gross Unrealized Gains 3 4
Gross Unrealized Losses (1) (8)
Estimated Fair Value 24,629 57,308
Total short-term investments [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Amortized Cost 24,627 57,312
Gross Unrealized Gains 3 4
Gross Unrealized Losses (1) (8)
Estimated Fair Value $ 24,629 $ 57,308