Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Sales of fuel cell systems and related infrastructure	$ 39,985	$ 78,002	$ 48,306
Services performed on fuel cell systems and related infrastructure	20,456	14,012	9,909
Power Purchase Agreements	13,687	5,718	2,137
Fuel delivered to customers	10,916	5,075	1,959
Other	884	481	1,919
Total revenue	85,928	103,288	64,230
Cost of revenue:
Sales of fuel cell systems and related infrastructure	29,543	67,703	43,378
Services performed on fuel cell systems and related infrastructure	22,649	22,937	19,256
Provision for loss contracts related to service	(1,071)	10,050
Power Purchase Agreements	16,132	5,253	1,052
Fuel delivered to customers	13,864	6,695	2,204
Other	865	540	3,202
Total cost of revenue	81,982	113,178	69,092
Gross profit (loss)	3,946	(9,890)	(4,862)
Operating expenses:
Research and development	21,177	14,948	6,469
Selling, general and administrative	34,288	34,164	26,601
Total operating expenses	55,465	49,112	33,070
Operating loss	(51,519)	(59,002)	(37,932)
Interest and other (expense) income, net	(10,704)	(349)	1,379
Change in fair value of common stock warrant liability	4,344	3,661	(52,260)
Loss before income taxes	(57,879)	(55,690)	(88,813)
Income tax benefit	392		325
Net loss attributable to the Company	(57,487)	(55,690)	(88,488)
Preferred stock dividends declared	(104)	(105)	(156)
Net loss attributable to common shareholders	$ (57,591)	$ (55,795)	$ (88,644)
Net loss per share:
Basic and diluted (in dollars per share)	$ (0.32)	$ (0.32)	$ (0.56)
Weighted average number of common shares outstanding	180,619,860	176,067,231	159,228,815