Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Details)
3 Months Ended 12 Months Ended
Dec. 31, 2017
USD ($)
Dec. 31, 2018
USD ($)
Customer
Segment
Dec. 31, 2017
USD ($)
Customer
Dec. 31, 2016
USD ($)
Customer
Significant Accounting Policies [Line Items]        
Standard warranty period offered   3 years    
Cash payments received in advance of satisfying performance obligations   $ 6,909,000 $ 4,290,000  
Performance obligation partially offset of revenue recognized $ 752,000 2,855,000 752,000  
Deferred capped rental revenue 0 $ 0 0  
Rental revenue earned   30 days    
Accounts receivable, net 31,444,000 $ 37,041,000 31,444,000  
Unbilled Receivables 1,470,000 589,000 1,470,000  
Increase in provision for bad debt and revenue adjustments related to prior years   $ 1,757,000 3,442,000  
Percentage of Non-US revenue invoiced in Euros   74.80%    
Transfer of inventory to rental equipment   $ 1,187,000 1,055,000 $ 1,454,000
Salvage value of expenditures for additions, improvements and replacements   0    
Repairs and maintenance expense   2,289,000 2,385,000 2,464,000
Depreciation and amortization   10,030,000 11,795,000 13,457,000
Impairments of long-lived assets   0 0  
Goodwill impairment loss   0 0  
Advertising costs   30,755,000 12,511,000 6,215,000
Unrecognized tax benefits, interest or penalties recognized   $ 0 $ 0 $ 0
Corporate tax rate   21.00% 34.00% 34.00%
Provision for income taxes related TCJA 7,578,000      
Additional adjustment to provisional amount related to TCJA 0      
Number of operating segments | Segment   1    
Number of reportable segments | Segment   1    
ASU 2016-02        
Significant Accounting Policies [Line Items]        
Operating lease, right-of-use asset   $ 6,400,000    
Operating lease, liability   6,400,000    
Construction in Process and Computer Software or Development Cost        
Significant Accounting Policies [Line Items]        
Depreciation and amortization   0 $ 0 $ 0
Other Noncurrent Assets        
Significant Accounting Policies [Line Items]        
Noncurrent inventories expected to be realized or consumed 644,000 1,085,000 644,000  
Customer Concentration Risk | Customer One        
Significant Accounting Policies [Line Items]        
Accounts receivable, net 10,394,000 16,198,000 10,394,000  
Customer Concentration Risk | Customer Two        
Significant Accounting Policies [Line Items]        
Accounts receivable, net 6,459,000 $ 4,155,000 $ 6,459,000  
Sales Revenue, Net | Customer Concentration Risk        
Significant Accounting Policies [Line Items]        
Number of customers | Customer   1 1 1
Concentration risk, percentage   10.00% 10.00% 12.40%
Net Accounts Receivable | Customer Concentration Risk        
Significant Accounting Policies [Line Items]        
Number of customers | Customer   2 2  
Concentration risk, percentage   10.00% 10.00%  
Sales Revenue, Services, Net | Customer Concentration Risk        
Significant Accounting Policies [Line Items]        
Concentration risk, percentage       72.60%
Raw materials | Supplier Concentration Risk | Vendor one        
Significant Accounting Policies [Line Items]        
Concentration risk, percentage   20.00% 19.70%  
Raw materials | Supplier Concentration Risk | Vendor two        
Significant Accounting Policies [Line Items]        
Concentration risk, percentage   11.90% 15.40%  
Raw materials | Supplier Concentration Risk | Vendor three        
Significant Accounting Policies [Line Items]        
Concentration risk, percentage   10.20% 9.50%  
Forward Contracts        
Significant Accounting Policies [Line Items]        
Payable   $ 472,000    
Accounts receivable, net $ 66,000   $ 66,000  
Lifetime Warranties | Direct-to-Consumer        
Significant Accounting Policies [Line Items]        
Sales revenue   $ 14,874,000 $ 10,820,000