Annual report pursuant to Section 13 and 15(d)

Concentrations - Summary of Net Revenue from Various Products (Detail)

v3.8.0.1
Concentrations - Summary of Net Revenue from Various Products (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Concentration Risk [Line Items]      
Net revenue $ 46,926 $ 51,810 $ 48,475
Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 100.00% 100.00% 100.00%
Laser systems      
Concentration Risk [Line Items]      
Net revenue $ 29,121 $ 35,150 $ 32,691
Laser systems | Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 62.00% 67.90% 67.50%
Imaging systems      
Concentration Risk [Line Items]      
Net revenue $ 3,685 $ 3,066 $ 2,237
Imaging systems | Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 7.90% 5.90% 4.60%
Consumables and other      
Concentration Risk [Line Items]      
Net revenue $ 7,332 $ 6,906 $ 6,877
Consumables and other | Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 15.60% 13.30% 14.20%
Services      
Concentration Risk [Line Items]      
Net revenue $ 6,660 $ 6,539 $ 6,465
Services | Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 14.20% 12.60% 13.30%
License fees and royalties      
Concentration Risk [Line Items]      
Net revenue $ 128 $ 149 $ 205
License fees and royalties | Product Concentration Risk | Sales Revenue, Net      
Concentration Risk [Line Items]      
Concentration Risk Percentage 0.30% 0.30% 0.40%