Quarterly report pursuant to Section 13 or 15(d)

Balance Sheet Components - Additional Information (Details)

v3.19.2
Balance Sheet Components - Additional Information (Details)
3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Jun. 30, 2019
USD ($)
Customer
Jun. 30, 2018
USD ($)
Customer
Dec. 31, 2018
USD ($)
Schedule Of Balance Sheet Components [Line Items]          
Unbilled Receivables $ 634,000   $ 634,000   $ 589,000
Accounts receivable, net $ 46,721,000   $ 46,721,000   37,041,000
Percentage of Non-US revenue invoiced in Euros 71.80% 76.00% 71.60% 76.40%  
Salvage value of expenditures for additions, improvements and replacements $ 0   $ 0    
Repairs and maintenance expense 701,000 $ 630,000 1,363,000 $ 1,190,000  
Depreciation and amortization 2,436,000 2,517,000 4,902,000 5,212,000  
Impairments of long-lived assets     0 0  
Impairment of finite lived intangible assets     0 0  
Amortization of intangible assets 324,000 $ 299,000 652,000 597,000  
Construction in Process and Computer Software or Development Cost          
Schedule Of Balance Sheet Components [Line Items]          
Depreciation and amortization     0 $ 0  
Other Noncurrent Assets          
Schedule Of Balance Sheet Components [Line Items]          
Noncurrent inventories expected to be realized or consumed 1,119,000   1,119,000   1,085,000
Customer Concentration Risk | Customer One          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net 18,989,000   18,989,000   16,198,000
Customer Concentration Risk | Customer Two          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net $ 6,159,000   $ 6,159,000   $ 4,155,000
Sales Revenue, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     0 1  
Net Accounts Receivable | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     2    
Raw materials | Supplier Concentration Risk | Vendor one          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     21.50% 20.20%  
Raw materials | Supplier Concentration Risk | Vendor two          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     13.10% 13.80%  
Raw materials | Supplier Concentration Risk | Vendor three          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     9.30% 9.30%