Fair Value Measurements and Other Financial Instruments - Additional Information (Detail) - Intellibot Robotics LLC [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2015	Jun. 30, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Purchase price of acquisition	$ 18.0
Cash paid for acquisition	9.0
Fair value of contingent consideration	$ 9.0	$ 9.6
Business acquisition contingent consideration payable period	10 years
Fair value of contingent consideration included in current liability		0.8
Fair value of contingent consideration included in non-current liability		8.8
Selling, General and Administrative Expenses [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value recognized in selling, general and administrative expense.		$ 0.2