Commitments and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended			3 Months Ended	12 Months Ended
	Aug. 31, 2020	Jun. 30, 2020 ft² Options Building	Apr. 30, 2020 m²	Mar. 31, 2025 USD ($)	Dec. 31, 2027 USD ($)	Dec. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jan. 31, 2023 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Operating lease right-of-use asset							$ 36,606	$ 46,508
Lease liabilities							59,180
Non Cash Lease Impairment Expense				$ 1,900
Sublease income							(4,622)	0	$ 0
Variable sublease income							1,400
Payment for sublease					$ 500	$ 5,700
Variable lease expenses							3,250	3,320	3,618
Current portion of tenant improvement allowance payable							20,607	11,030
Operating Lease, Cost							12,245	12,988	13,192
Lonza
Commitments And Contingencies Disclosure [Line Items]
Leasehold improvements and machinery and equipment										$ 81,700
Lonza \| Service Agreements
Commitments And Contingencies Disclosure [Line Items]
Cancelable and/ or non-cancelable contractual obligations, total							23,900
Unrecorded unconditional purchase obligation, expenses recognized							34,800	$ 25,800	$ 59,700
Clinical and Commercial Supply of Drug Substance \| Manufacturing Agreement \| Lonza
Commitments And Contingencies Disclosure [Line Items]
Unrecorded unconditional purchase obligation, expenses recognized							$ 86,500
Clinical and Commercial Supply of Drug Substance \| Maximum \| Manufacturing Agreement \| Lonza
Commitments And Contingencies Disclosure [Line Items]
Manufacturing agreement initial term	8 years
Manufacturing agreement term that can be extended	16 years
Lease Agreement on June 2020 \| Maximum
Commitments And Contingencies Disclosure [Line Items]
Lease area \| ft²		83,000
Lease Agreement on June 2020 \| Minimum
Commitments And Contingencies Disclosure [Line Items]
Lease area \| ft²		73,000
Lease Agreement on June 2020 \| California
Commitments And Contingencies Disclosure [Line Items]
Number of buildings leased \| Building		2
Initial lease term		6 years 6 months
Lease Agreement on June 2020 \| 1200 Page Mill Road in Palo Alto \| California
Commitments And Contingencies Disclosure [Line Items]
Lessee operating lease option to extend		6.5 years
Lease Agreement on June 2020 \| 1250 Page Mill Road in Palo Alto \| California
Commitments And Contingencies Disclosure [Line Items]
Initial lease term		13 years
Lessee operating lease option to extend		five
Number of options to extend lease term \| Options		2
Lease Agreement on April 2020 \| Rottenstrasse 5 in Visp \| Switzerland
Commitments And Contingencies Disclosure [Line Items]
Lease area \| m²			1,000
Initial lease term			5 years
Automatic renewal interval			5 years
Lease Agreement on April 2020 \| Rottenstrasse 5 in Visp \| Switzerland \| Maximum
Commitments And Contingencies Disclosure [Line Items]
Lessee, operating lease, term of contract			15 years

Kodiak Sciences Inc. 10-K