Leases - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) Lease	Apr. 30, 2020 Lease	Dec. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Sublease, description of option to extend	lease amendments that provide for additional office space in Davis, CA, and extend the term through April 2025, with one option to renew for an additional five-year term. The Company expects to exercise its options to renew, and in accordance with ASC 842, accounted for the amendment and expected renewal as a lease modification and remeasured the operating lease liability
Number of lease amendments | Lease	3	2
Operating Lease, Liability	$ 6,274		$ 2,108
Right of use asset	$ 6,013		$ 1,963
Existence of option to extend	true
Lease option to extend, description	Some leases (the Davis office, warehouse, greenhouse and a copy machine) include one or more options to renew, with renewal terms that can extend the lease term from one to six years.
Minimum [Member]
Lessee Lease Description [Line Items]
Option to extend lease, term	1 year
Operating leases, term of contract	1 year
Maximum [Member]
Lessee Lease Description [Line Items]
Option to extend lease, term	6 years
Operating leases, term of contract	5 years
ASU No. 2016-02 [Member]
Lessee Lease Description [Line Items]
Operating Lease, Liability	$ 3,800
Right of use asset	$ 3,800
Premises And Equipment [Member]
Lessee Lease Description [Line Items]
Operating leases, term of contract	3 years
Molokai, HI, [Member]
Lessee Lease Description [Line Items]
Sublease, description of option to extend	lease amendment for additional parcels of land in Molokai, HI, modified the Molokai office space lease to extend the term by 12 months, and entered into new lease agreements for office equipment, collectively resulting in an additional $0.1 million of operating lease liabilities and right of use assets.
Operating Lease, Liability	$ 100
Right of use asset	$ 100
Woodland, CA and Oregon [Member]
Lessee Lease Description [Line Items]
Sublease, description of option to extend	lease amendment for the land and greenhouse in Woodland, CA, modified the Woodland lease to extend the term by 4 years collectively, and entered into a new lease for the premises and equipment related to the purchase of ISI in Oregon with a three-year term, resulting in an additional $0.5 million of operating lease liabilities and right of use assets.
Operating Lease, Liability	$ 500
Right of use asset	$ 500
Office Space [Member]
Lessee Lease Description [Line Items]
Option to extend lease, term	5 years
Office Space [Member] | Molokai, HI, [Member]
Lessee Lease Description [Line Items]
Option to extend lease, term	12 months
Office Space [Member] | Woodland, CA, [Member]
Lessee Lease Description [Line Items]
Option to extend lease, term	4 years