Industry and Geographic Information - Sales to Individual Customers in Excess of 10% of Total Revenues (Detail) - Sales [Member]	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Revenue, Major Customer [Line Items]
Sales percentage	10.00%
Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Sales percentage	53.00%	40.00%
Customer Concentration Risk [Member] \| Customer A [Member]
Revenue, Major Customer [Line Items]
Sales percentage	22.00%	14.00%
Customer Concentration Risk [Member] \| Customer B [Member]
Revenue, Major Customer [Line Items]
Sales percentage	16.00%	13.00%
Customer Concentration Risk [Member] \| Customer C [Member]
Revenue, Major Customer [Line Items]
Sales percentage	15.00%	13.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration