Restructuring Expenses - Additional Information (Detail) $ / qtr in Millions, $ in Millions		3 Months Ended		12 Months Ended
	May 06, 2014 $ / qtr	Jun. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
2014 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Reductions in company's worldwide workforce	20.00%
Reduction of overall cost structure | $ / qtr	2.0
Special charges for restructuring plan		$ 1.8
Severance costs for affected employees		0.4
Other restructuring related costs		0.1
Non-cash stock based compensation expense		$ 1.3
2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Reductions in company's worldwide workforce			26.00%
Special charges for restructuring plan					$ 5.6
Severance costs for affected employees					1.1
Other restructuring related costs					0.2
Annualized savings			$ 16.0
Lease/rental termination charges for restructuring				$ 0.8	3.3
Equipment and improvements write-offs due to lease/rental terminations				$ 0.6	$ 1.0