Quarterly report pursuant to Section 13 or 15(d)

Balance Sheet Components - Additional Information (Details)

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Balance Sheet Components - Additional Information (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2017
USD ($)
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
Customer
Jun. 30, 2016
USD ($)
Customer
Dec. 31, 2016
USD ($)
Customer
Schedule Of Balance Sheet Components [Line Items]          
Unbilled Receivables $ 5,565,000   $ 5,565,000   $ 7,484,000
Accounts receivable, net 34,803,000   34,803,000   30,828,000
Accounts receivable, net $ 34,803,000   $ 34,803,000   30,828,000
Percentage of Non-US revenue invoiced in Euros 75.40% 69.10% 73.90% 69.20%  
Noncurrent inventories expected to be realized or consumed $ 397,000   $ 397,000   314,000
Salvage value of expenditures for additions, improvements and replacements 0   0    
Repairs and maintenance expense 694,000 $ 746,000 1,345,000 $ 1,433,000  
Depreciation and amortization 2,992,000 3,404,000 6,169,000 6,829,000  
Impairments of long-lived assets 0 0 0 0  
Impairment of finite lived intangible assets 0 0 0 0  
Amortization of intangible assets 125,000 22,000 152,000 45,000  
Construction in Process and Computer Software or Development Cost          
Schedule Of Balance Sheet Components [Line Items]          
Depreciation and amortization 0 $ 0 0 $ 0  
Medicare          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net 5,039,000   5,039,000   7,208,000
Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net $ 11,055,000   $ 11,055,000   $ 9,791,000
Sales Revenue, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     1 0  
Concentration risk, percentage 7.10% 11.90% 8.00% 14.10%  
Net Accounts Receivable | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     1   1
Concentration risk, percentage     14.50%   23.40%
Sales Revenue, Services, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage 74.70% 72.20% 74.00% 71.80%  
Raw materials | Supplier Concentration Risk | Vendor one          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     18.60% 21.90%  
Raw materials | Supplier Concentration Risk | Vendor two          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     14.60% 13.60%  
Raw materials | Supplier Concentration Risk | Vendor three          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     9.80% 7.70%