Fair Value of Financial Instruments - Summary of Change in Estimated Fair Value of Company's Level 3 Financial Instrument (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	May. 19, 2015	May. 01, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability							$ 8,900
Change in the value of private placement warrants			$ (8,040)	$ (1,190)
Change in the value of contingent consideration		$ (3,208)	(50)	$ (3,782)
Balance ending	$ 8,690		8,690
Powertrain Integration, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	8,200		8,200		$ 8,200
Change in the value of contingent consideration	(50)		(50)
Bi-Phase Technologies, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	540		540			$ 540
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance beginning			11,036
Fair value of private placement warrants exercised			(255)
Change in the value of private placement warrants			(8,040)
Balance ending	$ 2,741		$ 2,741