Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Anti-dilutive shares (in shares)	3,107,116
Right-of-use assets	$ 8,447	$ 8,600
Current lease liabilities	985	300	$ 0
Noncurrent lease liabilities	$ 13,598	13,700
Lease incentives and deferred rent balance		$ 5,400