Restructuring - Schedule of Components of Liabilities (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring expenses	$ 1,492
Cash payments	608
Employee Severance And Other Benefits [Member] | Accrued Expenses and Other Current Liabilities [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expenses	1,492
Cash payments	608
Liability included in accrued expenses and other current liabilities at March 31, 2019	$ 884