Revenue - Estimated future revenue (Details) - USD ($)
$ in Thousands |
Jun. 30, 2018 |
Dec. 31, 2017 |
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
$ 221,914
|
|
| Sales of fuel cell systems |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
13,478
|
|
| Sale of hydrogen installations and other infrastructure |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
8,281
|
|
| Services performed on fuel cell systems and related infrastructure |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
77,496
|
|
| Power purchase agreements |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
$ 122,659
|
|
| Calculated under Revenue Guidance in Effect before Topic 606 [Member] |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
|
$ 260,931
|
| Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Sales of fuel cell systems |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
|
26,298
|
| Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Sale of hydrogen installations and other infrastructure |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
|
15,512
|
| Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Services performed on fuel cell systems and related infrastructure |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
|
89,079
|
| Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Power purchase agreements |
|
|
| Disaggregation of revenue |
|
|
| Total estimated future revenue |
|
$ 130,042
|