Restructuring, Impairment and Other Costs of Terminated Program - Narrative (Details) $ in Thousands			1 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2022	May 31, 2022	Apr. 30, 2022	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2022
Restructuring Cost and Reserve [Line Items]
Impairment of right-of-use assets and property, plant and equipment							$ 65,761	$ 0	$ 0
Book value in excess of fair value					$ 67,875
Third St. Facility
Restructuring Cost and Reserve [Line Items]
Book value in excess of fair value				$ 12,000
Measurement Input, Market Participant Subtenant Borrowing Rate
Restructuring Cost and Reserve [Line Items]
Operating lease, measurement input	7.90%	6.40%
Nektar 214 | Bristol-Myers Squibb
Restructuring Cost and Reserve [Line Items]
Reimbursement of expenses						$ 20,800
Employee Severance
Restructuring Cost and Reserve [Line Items]
Percent of positions eliminated			70.00%
Entity number of employees			225							735