Restructuring Expenses - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended
	Feb. 29, 2012	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]
Reduction in company's worldwide workforce		26.00%
Annualized savings	$ 7,000,000	$ 14,000,000
Special charges for restructuring plan		5,600,000
Lease/rental terminations charges for restructuring		3,200,000
Severance costs for affected employees		1,200,000
Equipment and improvements write-offs due to lease/rental terminations		1,000,000
Other restructuring related costs		200,000
Estimated restructuring cash expenditures		1,700,000
Percentage reduction of headcount	7.00%
One-time employee termination and other costs			200,000
2013 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Usage for lease/rental terminations		(1,651,000)
2013 Restructuring [Member] | Lease/rental terminations [Member]
Restructuring Cost and Reserve [Line Items]
Usage for lease/rental terminations		$ 138,000