Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net revenue:
Net revenue	$ 56,376	$ 53,165	$ 132,037	$ 114,812
Cost of revenue:
Total cost of revenue	51,114	48,756	123,391	116,697
Gross loss (profit)	5,262	4,409	8,646	(1,885)
Operating expenses:
Research and development	8,028	8,402	24,334	25,477
Selling, general and administrative	10,400	8,652	33,351	29,202
Total operating expenses	18,428	17,054	57,685	54,679
Operating loss	(13,166)	(12,645)	(49,039)	(56,564)
Interest and other expense, net	(8,490)	(6,352)	(24,696)	(15,593)
Change in fair value of common stock warrant liability	427	1,716	7	3,308
Loss before income taxes	(21,229)	(17,281)	(73,728)	(68,849)
Income tax benefit		1,716		7,581
Net loss attributable to the Company	(21,229)	(15,565)	(73,728)	(61,268)
Preferred stock dividends declared and accretion of discount	(13)	(13)	(39)	(39)
Net loss attributable to common stockholders	$ (21,242)	$ (15,578)	$ (73,767)	$ (61,307)
Net loss per share:
Basic and diluted	$ (0.09)	$ (0.07)	$ (0.32)	$ (0.28)
Weighted average number of common stock outstanding	236,759,521	218,953,106	229,519,323	218,930,891
Sales of fuel cell systems and related infrastructure
Net revenue:
Net revenue	$ 38,165	$ 36,668	$ 78,932	$ 66,101
Cost of revenue:
Total cost of revenue	24,990	27,428	50,440	52,927
Services performed on fuel cell systems and related infrastructure
Net revenue:
Net revenue	5,920	5,156	17,415	16,330
Cost of revenue:
Total cost of revenue	6,461	5,302	18,802	17,139
Power Purchase Agreements
Net revenue:
Net revenue	5,599	5,555	16,613	16,365
Cost of revenue:
Total cost of revenue	10,353	8,767	28,064	27,055
Fuel delivered to customers
Net revenue:
Net revenue	6,557	5,786	18,942	16,016
Cost of revenue:
Total cost of revenue	9,160	$ 7,259	25,935	$ 19,576
Other
Net revenue:
Net revenue	135		135
Cost of revenue:
Total cost of revenue	$ 150		$ 150