Revenue - Estimated future revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Revenue
Total estimated future revenue	$ 1,151,431
Sales of fuel cell systems
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Total estimated future revenue	$ 64,954
Sale of hydrogen installations and other infrastructure
Revenue
Total estimated future revenue	$ 22,860
Sale of electrolyzers
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Total estimated future revenue	$ 301,323
Sales of engineered equipment
Revenue
Total estimated future revenue	19,876
Services performed on fuel cell systems and related infrastructure
Revenue
Total estimated future revenue	123,080
Power purchase agreements
Revenue
Total estimated future revenue	435,967
Fuel delivered to customers and related equipment
Revenue
Total estimated future revenue	$ 95,444
Sales of cryogenic equipment and other
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Total estimated future revenue	$ 87,927
Maximum | Sales of fuel cell systems
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	2 years
Maximum | Sale of electrolyzers
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	2 years
Maximum | Services performed on fuel cell systems and related infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	10 years
Maximum | Power purchase agreements
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	10 years
Maximum | Fuel delivered to customers and related equipment
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	10 years
Minimum | Sales of fuel cell systems
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Minimum | Sale of electrolyzers
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Minimum | Services performed on fuel cell systems and related infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	5 years
Minimum | Power purchase agreements
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	5 years
Minimum | Fuel delivered to customers and related equipment
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	5 years