Revenue - Estimated future revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)
Revenue
Total estimated future revenue	$ 890,644
Sales of fuel cell systems
Revenue
Total estimated future revenue	$ 34,555
Sale of hydrogen installations and other infrastructure
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Total estimated future revenue	$ 19,425
Sales of electrolyzers
Revenue
Total estimated future revenue	$ 225,329
Sales of engineered equipment
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	1 year
Total estimated future revenue	$ 2,332
Services performed on fuel cell systems and related infrastructure
Revenue
Total estimated future revenue	122,900
Power purchase agreements
Revenue
Total estimated future revenue	356,815
Fuel delivered to customers and related equipment
Revenue
Total estimated future revenue	$ 69,152
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	$ 60,136
Maximum | Sales of fuel cell systems
Revenue
Duration of estimated revenue expected to be recognized in future (in years)	2 years
Maximum | Sales 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 | Sales 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