The Company and Subsequent Events - Summary of Reconciliation of Beginning and Ending Restructuring Liability (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restructuring Cost And Reserve [Line Items]
Balance, beginning of period	$ 2,547
Additions, charged to restructuring expenses	1,914	$ 865
Payments	(3,103)
Balance, end of period	1,358
One-Time Employee Termination Benefit Costs
Restructuring Cost And Reserve [Line Items]
Balance, beginning of period	2,079
Additions, charged to restructuring expenses	646
Payments	(1,675)
Balance, end of period	1,050
Contract Termination Costs
Restructuring Cost And Reserve [Line Items]
Balance, beginning of period	389
Additions, charged to restructuring expenses	4
Payments	(88)
Balance, end of period	305
Consulting Costs
Restructuring Cost And Reserve [Line Items]
Balance, beginning of period	79
Additions, charged to restructuring expenses	839
Payments	(915)
Balance, end of period	3
Asset Disposal Costs
Restructuring Cost And Reserve [Line Items]
Additions, charged to restructuring expenses	425
Payments	$ (425)