Annual report pursuant to Section 13 and 15(d)

Intangible Assets and Related Accumulated Amortization (Detail)

v3.10.0.1
Intangible Assets and Related Accumulated Amortization (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Intangible Assets And Goodwill [Line Items]    
Intangible assets, gross $ 2,800 $ 2,800
Intangible assets, accumulated amortization $ (2,800) $ (2,800)
Useful life indefinite life indefinite life
Goodwill gross $ 2,926 $ 2,926
Goodwill 2,926 2,926
Patents    
Intangible Assets And Goodwill [Line Items]    
Intangible assets, gross 1,914 1,914
Intangible assets, accumulated amortization $ (1,914) $ (1,914)
Patents | Minimum    
Intangible Assets And Goodwill [Line Items]    
Useful life 4 years 4 years
Patents | Maximum    
Intangible Assets And Goodwill [Line Items]    
Useful life 10 years 10 years
Trademarks    
Intangible Assets And Goodwill [Line Items]    
Useful life 6 years 6 years
Intangible assets, gross $ 69 $ 69
Intangible assets, accumulated amortization (69) (69)
Other Intangible Assets    
Intangible Assets And Goodwill [Line Items]    
Intangible assets, gross 817 817
Intangible assets, accumulated amortization $ (817) $ (817)
Other Intangible Assets | Minimum    
Intangible Assets And Goodwill [Line Items]    
Useful life 4 years 4 years
Other Intangible Assets | Maximum    
Intangible Assets And Goodwill [Line Items]    
Useful life 6 years 6 years