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 9 Months Ended 12 Months Ended
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
Customer
Sep. 30, 2016
USD ($)
Customer
Dec. 31, 2016
USD ($)
Customer
Schedule Of Balance Sheet Components [Line Items]          
Unbilled Receivables $ 3,117,000   $ 3,117,000   $ 7,484,000
Accounts receivable, net $ 34,699,000   $ 34,699,000   30,828,000
Percentage of Non-US revenue invoiced in Euros 77.20% 72.80% 75.20% 70.70%  
Noncurrent inventories expected to be realized or consumed $ 391,000   $ 391,000   314,000
Salvage value of expenditures for additions, improvements and replacements 0   0    
Repairs and maintenance expense 463,000 $ 497,000 1,808,000 $ 1,930,000  
Depreciation and amortization 2,835,000 3,388,000 9,004,000 10,217,000  
Impairments of long-lived assets 0 0 0 0  
Impairment of finite lived intangible assets 0 0 0 0  
Amortization of intangible assets 101,000 28,000 253,000 73,000  
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 2,877,000   2,877,000   7,208,000
Customer Concentration Risk | Customer One          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net 11,790,000   11,790,000   $ 9,791,000
Customer Concentration Risk | Customer Two          
Schedule Of Balance Sheet Components [Line Items]          
Accounts receivable, net $ 4,960,000   $ 4,960,000    
Sales Revenue, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     1 0  
Concentration risk, percentage 6.00% 9.50% 7.30% 12.40%  
Net Accounts Receivable | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Number of customers | Customer     2   1
Concentration risk, percentage     8.30%   23.40%
Sales Revenue, Services, Net | Customer Concentration Risk          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage 70.10% 71.00% 72.80% 71.60%  
Raw materials | Supplier Concentration Risk | Vendor one          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     19.90% 22.00%  
Raw materials | Supplier Concentration Risk | Vendor two          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     13.90% 14.90%  
Raw materials | Supplier Concentration Risk | Vendor three          
Schedule Of Balance Sheet Components [Line Items]          
Concentration risk, percentage     9.70% 7.90%