Summary of Significant Accounting Policies - Summary of Accounts Receivable from OEM Customers in Excess of 10% of Total Accounts Receivable (Detail) (Accounts receivable [Member])	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Customer A [Member]
Concentration Risk [Line Items]
Accounts receivable in excess of 10% of total accounts receivable	16.00%	0.00%
Customer B [Member]
Concentration Risk [Line Items]
Accounts receivable in excess of 10% of total accounts receivable	13.00%	4.00%
Customer C [Member]
Concentration Risk [Line Items]
Accounts receivable in excess of 10% of total accounts receivable	10.00%	8.00%
Customer D [Member]
Concentration Risk [Line Items]
Accounts receivable in excess of 10% of total accounts receivable	8.00%	30.00%