Restructuring Charges - Roll Forward of Accrued Restructuring Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2015	$ 0
Restructuring charges	1,642	$ 0	$ 534
Payments	(201)
Accelerated depreciation	(379)
Accrued at December 31, 2015	1,062	0
Severance expenses
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2015	0
Restructuring charges	73
Payments	(73)
Accelerated depreciation	0
Accrued at December 31, 2015		0
Write-downs and retirements of fixed assets
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2015	0
Restructuring charges	607
Payments	0
Accelerated depreciation	(379)
Accrued at December 31, 2015	228	0
Lease cancellations
Restructuring Reserve [Roll Forward]
Accrued at January 1, 2015	0
Restructuring charges	962
Payments	(128)
Accelerated depreciation	0
Accrued at December 31, 2015	$ 834	$ 0