Commitments and Contingencies- Additional Information (Detail)
 1 Months Ended 12 Months Ended
Dec. 31, 2015
USD ($)
ft²
May 31, 2007
ft²
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
ft²
Dec. 31, 2005
ft²
Jul. 31, 2020
USD ($)
Jul. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Jul. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Aug. 01, 2014
ft²
Aug. 31, 2012
ft²
Other Commitments [Line Items]                        
Area of leased property property | ft²         126,352              
Additional area of under capital lease | ft²   20,000                    
Capital lease interest rate (as percent)         6.50%              
Area of lease reduction due to downsize | ft² 150,000     150,000                
Possible early termination fee $ 300,000     $ 300,000                
Restructuring charges     $ 2,103,000 1,311,000                
Corporate guaranty for capital lease     P5Y                  
Rent expense     $ 1,100,000 1,400,000                
Non-cancelable purchase obligations primarily related to inventory purchases     1,100,000                  
Royalty commitment $ 200,000   400,000 200,000                
Lease related [Member]                        
Other Commitments [Line Items]                        
Restructuring charges       $ 331,000                
Haywood, California [Member] | Lease related [Member]                        
Other Commitments [Line Items]                        
Restructuring charges     $ 314,000                  
Forecast [Member]                        
Other Commitments [Line Items]                        
Royalty commitment               $ 100,000   $ 400,000    
Forecast [Member] | Early Lease Termination Fee [Member]                        
Other Commitments [Line Items]                        
Possible early termination fee           $ 429,736 $ 934,814   $ 1,512,679      
Lease Amendment [Member]                        
Other Commitments [Line Items]                        
Area of leased office space | ft²                     184,813 184,813