Future Minimum Cash Payments Under Non-cancelable Operating Leases (Detail) $ in Thousands	Sep. 30, 2019 USD ($)
Leases [Abstract]
2019	$ 731	[1]
2020	1,942
2021	2,779
2022	2,659
2023	2,702
Thereafter	16,888
Total future minimum lease payments	27,701
Less: amount representing interest	3,580
Present value of minimum lease payments	$ 24,121

[1] Excludes the nine months ended September 30, 2019