Annual report pursuant to Section 13 and 15(d)

Revenues from Major Customers - Revenues from Major Customers (Parenthetical) (Detail)

v2.4.1.9
Revenues from Major Customers - Revenues from Major Customers (Parenthetical) (Detail) (Maximum [Member], Customer Concentration Risk [Member], Sales Revenue, Net [Member])
 12 Months Ended
Dec. 31, 2014
Maximum [Member] | Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
  
Revenue, Major Customer [Line Items]  
Maximum percentage of revenue 10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember