Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)

v3.8.0.1
Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
USD ($)
Segment
Dec. 31, 2017
USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]    
Standard warranty period offered 3 years  
Cash payments received in advance of satisfying distinct performance obligation $ 1,459  
Performance obligation offset of revenue recognized $ 286  
Rental revenue earned 30-day period  
Number of operating segments | Segment 1  
Number of reportable segments | Segment 1  
Lifetime Warranties | Direct-to-Consumer    
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]    
Sales revenue $ 11,993 $ 10,820