Annual report pursuant to Section 13 and 15(d)

Organization and Summary of Significant Accounting Policies - Additional Information (Detail)

v3.8.0.1
Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Jun. 30, 2016
Additional Details        
Restricted Cash and Cash Equivalents $ 2,500,000 $ 1,800,000    
Standard Product Warranty Accrual, Current 900,000 900,000    
Depreciation 12,000,000 $ 10,600,000 $ 10,800,000  
Impairment of Intangible Assets (Excluding Goodwill) $ 2,000,000      
Number of operating segments 1      
Minimum [Member]        
Additional Details        
Term Of Invoice Of Distributor 30 days      
Maximum [Member]        
Additional Details        
Term Of Invoice Of Distributor 60 days      
Adjustments for New Accounting Pronouncement [Member]        
Additional Details        
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets       $ 0
Revenue from Distributors [Member]        
Additional Details        
Concentration Risk, Percentage 34.00% 19.00% 13.00%  
Indefinite-lived Intangible Assets [Member]        
Additional Details        
Impairment of Intangible Assets (Excluding Goodwill) $ 2,000,000 $ 1,300,000 $ 21,600,000