Product Warranties - Additional Information (Detail)	9 Months Ended
Sep. 30, 2017
Guarantees [Abstract]
Product warranty period	2 years
Extended product warranty period	3 years
Extended product warranty description	Effective January 1, 2017, the Company extended the warranty period to three years for certain military grade products sold after that date.

Describes the nature of the extended product warranties, which generally require additional fees to be paid by the buyer, and other guarantee contracts excluded from the initial recognition and initial measurement requirements. Does not include disclosures for standard product warranties, which typically have substantially shorter periods of time or provide less coverage, or both.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12069-110248

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