Summary of Significant Accounting Policies - Warranty (Details)	12 Months Ended
Dec. 31, 2017
Minimum
Warranty
Standard product warranty period	1 year
Extended product warranty period	1 year
Maximum
Warranty
Standard product warranty period	2 years
Extended product warranty period	4 years

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ProductWarrantyLiabilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration