Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue
Net revenue	$ 124,557	$ 67,995	$ 196,515	$ 108,814
Sales of fuel cell systems
Revenue
Net revenue	59,169	40,785	85,588	55,425
Sale of hydrogen installations and other infrastructure
Revenue
Net revenue	40,109	6,961	60,462	12,789
Services performed on fuel cell systems and related infrastructure
Revenue
Net revenue	5,675	6,236	11,720	12,757
Power Purchase Agreements
Revenue
Net revenue	8,361	6,579	16,187	13,000
Fuel delivered to customers
Revenue
Net revenue	11,121	7,372	22,248	14,705
Other
Revenue
Net revenue	$ 122	$ 62	$ 310	$ 138