Defined Contribution Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Professional Power Products, Inc. [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined benefit plan discretionary contributions	$ 0	$ 0	$ 0
Defined benefit plan matching contributions	98,000	$ 91,000
Powertrain Integration, LLC [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined benefit plan discretionary contributions	$ 0