Leases - Additional Information (Detail) $ in Millions	1 Months Ended			3 Months Ended	6 Months Ended
	Feb. 28, 2019 ft²	Jun. 30, 2012 ft²	Dec. 31, 2011 ft²	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)
Leases [Line Items]
Lessee, operating lease, existence of option to extend					true
Fixed lease expense					$ 2.4	$ 2.4
Variable lease expense					0.2	$ 0.2
Operating sublease income				$ 0.1	0.2
Los Angeles, California
Leases [Line Items]
Percentage of increase in annual rent	3.00%
Existing square feet of subleased property | ft²	12,429
Sublease expiration date	Mar. 31, 2026
Lease Agreement executed on December 2011
Leases [Line Items]
Office lease, lease term			7 years
Existing square feet of leased property | ft²			65,656
Lease expiration date			Mar. 31, 2026
Percentage of increase in annual rent			3.00%
Office space, lease extension Stand-by letter of credit				2.0	2.0		$ 2.5
Office space, decrease in lease extension Stand-by letter of credit				0.5
Lease Agreement executed on June 2012
Leases [Line Items]
Existing square feet of leased property | ft²		29,470
Lease expiration date		Mar. 31, 2026
Percentage of increase in annual rent		3.00%
Office space, lease extension Stand-by letter of credit				1.1	$ 1.1		$ 1.6
Office space, decrease in lease extension Stand-by letter of credit				$ 0.5
Lessee, operating lease, existence of option to extend		true
Lease option to extend, term		5 years