Commitments and Contingencies - Operating Leases - Additional Information (Detail) - ft²				1 Months Ended			3 Months Ended
	Dec. 01, 2018	Oct. 01, 2018	Aug. 01, 2018	Oct. 31, 2018	May 31, 2018	Apr. 30, 2018	Mar. 31, 2018
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease							54,943
Lease expire date							Aug. 15, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease						40,419	19,805
Lease expire date						Aug. 31, 2024	Feb. 28, 2022
Increased office space rent			13,481			20,614
Operating Lease Two [Member] | Subsequent Event [Member]
Commitments And Contingencies [Line Items]
Increased office space rent		7,133
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease					15,525
Lease expire date					Nov. 30, 2024
Operating Lease Four [Member] | Scenario, Forecast [Member]
Commitments And Contingencies [Line Items]
Increased office space rent	3,499
Operating Lease Four [Member] | Subsequent Event [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease				58,442
Lease expire date				Aug. 31, 2024
Increased office space rent				54,943