Quarterly report pursuant to Section 13 or 15(d)

Balance Sheet Components - Additional Information (Details)

v3.10.0.1
Balance Sheet Components - Additional Information (Details)
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Jun. 30, 2018
USD ($)
Customer
Jun. 30, 2017
USD ($)
Customer
Dec. 31, 2017
USD ($)
Customer
Schedule Of Balance Sheet Components [Line Items]          
Unbilled Receivables $ 1,251,000   $ 1,251,000   $ 1,470,000
Accounts receivable, net $ 37,472,000   $ 37,472,000   31,444,000
Percentage of Non-US revenue invoiced in Euros 76.00% 75.40% 76.40% 73.90%  
Noncurrent inventories expected to be realized or consumed $ 312,000   $ 312,000   644,000
Salvage value of expenditures for additions, improvements and replacements 0   0    
Repairs and maintenance expense 630,000 $ 694,000 1,190,000 $ 1,345,000  
Depreciation and amortization 2,517,000 2,992,000 5,212,000 6,169,000  
Impairments of long-lived assets 0 0 0 0  
Impairment of finite lived intangible assets 0 0 0 0  
Amortization of intangible assets 299,000 125,000 597,000 152,000  
Construction in Process and Computer Software or Development Cost          
Schedule Of Balance Sheet Components [Line Items]          
Depreciation and amortization 0 $ 0 0 $ 0  
Customer Concentration Risk | Customer One          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net 10,763,000   10,763,000   10,394,000
Customer Concentration Risk | Customer Two          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net $ 6,484,000   $ 6,484,000   $ 6,459,000
Sales Revenue, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     1 1  
Net Accounts Receivable | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     2   2
Raw materials | Supplier Concentration Risk | Vendor one          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     20.20% 18.60%  
Raw materials | Supplier Concentration Risk | Vendor two          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     13.80% 14.60%  
Raw materials | Supplier Concentration Risk | Vendor three          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     9.30% 9.80%