Leases - Additional Information (Detail) $ in Thousands	1 Months Ended			12 Months Ended
	Oct. 31, 2018 ft²	Aug. 01, 2018 USD ($)	Mar. 31, 2017 USD ($) ft² Lease	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Lessee Lease Description [Line Items]
Number of lease renewal option | Lease			1
Rent expense				$ 2,500
Short term and variable lease cost				500
Cash paid for measurement of lease obligations for operating cash flows from operating leases				$ 2,700
Weighted average remaining lease term				4 years 7 months 6 days
Weighted average discount rate				7.75%
Operating lease payments					$ 15,785
Option to extend, existence, operating facility lease			true	true
Property and equipment, net				$ 1,808	32
Build-to-suit obligation					7,324
Build-to-suit related to construction costs incurred					3,500
Build-to-suit rent expense					300
Assets Held under Operating Leases [Member]
Lessee Lease Description [Line Items]
Property and equipment, net					8,900
1020 Space [Member]
Lessee Lease Description [Line Items]
Operating facility lease area | ft²			34,500
Lease commencement date			2017-08
Operating facility lease term			87 months
Lease agreement, one renewal option term			5 years
Lease agreement, additional extended lease term			5 years
Tenant improvement allowance			$ 1,900
Letter of credit to secure lease obligations			2,400
Operating lease payments			$ 20,000
1020 Space [Member] | Sublease Agreement [Member] | EVA Automation, Inc [Member]
Lessee Lease Description [Line Items]
Operating facility lease term		73 months
Sublease commencement date		Oct. 01, 2018
Abatement of base rent lease payment		$ 900
Operating lease abatement term		5 months
Operating lease payments receivable				2,500	$ 600
Cash received from sublease				$ 2,300
1020 Space [Member] | Lease Agreement [Member]
Lessee Lease Description [Line Items]
Operating facility lease term			86 months
Palo Alto, California [Member] | Sublease Agreement [Member]
Lessee Lease Description [Line Items]
Operating facility lease area | ft²	4,240
Lease commencement date	2018-10
Lease expires date	Aug. 31, 2020
1060 Marsh Road [Member]
Lessee Lease Description [Line Items]
Operating facility lease area | ft²			17,400