Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Summary of Cash and Cash Equivalents and Short Term Investments (Detail)

v3.6.0.2
Fair Value Measurements - Summary of Cash and Cash Equivalents and Short Term Investments (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Cash, amortized cost and estimated fair value $ 1,800 $ 14,034    
Cash and cash equivalents, amortized cost and estimated fair value 15,233 34,310 $ 27,897 $ 14,593
Restricted cash, amortized cost and estimated fair value 272 272    
Amortized Cost 10,231 20,885    
Gross Unrealized Losses (1) (9)    
Estimated Fair Value 10,230 20,876    
Restricted cash, amortized cost and estimated fair value   272    
Money market securities [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Cash equivalents, amortized cost and estimated fair value 11,931 20,276    
Restricted cash, amortized cost and estimated fair value 272      
Restricted cash, amortized cost and estimated fair value   272    
Corporate bonds and commercial paper (cash and cash equivalents) [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Cash equivalents, amortized cost and estimated fair value 1,502      
Corporate bonds and commercial paper (short term investments) [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Amortized Cost 8,231 20,885    
Gross Unrealized Losses (1) (9)    
Estimated Fair Value 8,230 $ 20,876    
Government securities [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Amortized Cost 2,000      
Estimated Fair Value $ 2,000