Summary of Lease Costs Recognized Under Topic 842 and Other Information Pertaining to Operating Leases (Detail) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lease cost
Operating lease cost	$ 2,606	$ 7,738
Variable lease cost	1,008	2,946
Total lease cost	$ 3,614	10,684
Other information
Operating lease payments		$ 7,606
Weighted average remaining lease term	5 years 8 months 12 days	5 years 8 months 12 days
Weighted average discount rate	7.50%	7.50%