Leases - Additional Information (Detail) $ in Thousands	1 Months Ended				3 Months Ended		12 Months Ended
	Aug. 31, 2020 USD ($) ft²	Oct. 31, 2018 ft²	Aug. 01, 2018 USD ($)	Mar. 31, 2017 ft² Lease	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Lessee Lease Description [Line Items]
Number of lease renewal option | Lease				1
Cash paid for measurement of lease obligations for operating cash flows from operating leases					$ 300	$ 700
Short term and variable lease cost					100	100
Rent expense					$ 400	800
Weighted average remaining lease term					3 years 8 months 12 days
Weighted average discount rate					7.64%
Write down of sublease receivable balance and previously capitalized commission charges						1,383
2479 E. Bayshore Blvd, 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
North Carolina [Member]
Lessee Lease Description [Line Items]
Operating facility lease area | ft²	4,128
Operating facility lease term	63 months
Operating lease abatement term	3 months
Cash paid for measurement of lease obligations for operating cash flows from operating leases	$ 9
1020 Marsh Road, Menlo Park, California [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
1020 Marsh Road, Menlo Park, California [Member] | Sublease Agreement [Member] | EVA Automation, Inc [Member]
Lessee Lease Description [Line Items]
Operating facility lease term			72 months
Operating lease abatement term			5 months
Sublease commencement date			Oct. 01, 2018
Abatement of base rent lease payment			$ 900
Write down of sublease receivable balance and previously capitalized commission charges						1,400
Operating lease sublease income (loss)						(700)	$ (13)
Cash received from sublease						$ 400	$ 1,200