Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Schedule of Changes in Aggregate Product Warranty Liabilities (Details)

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Commitments and Contingencies - Schedule of Changes in Aggregate Product Warranty Liabilities (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]      
Product warranty liability at beginning of period $ 3,480 $ 1,973 $ 1,115
Accruals for warranties issued 5,275 3,123 1,871
Adjustments related to preexisting warranties (including changes in estimates) 200 118 510
Settlements made (in cash or in kind) (2,784) (1,734) (1,523)
Product warranty liability at end of period $ 6,171 $ 3,480 $ 1,973