Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net revenue:
Net revenue	$ 57,068	$ 35,229	$ 75,661	$ 61,647
Cost of revenue:
Total cost of revenue	46,914	37,539	72,277	67,941
Gross profit (loss)	10,154	(2,310)	3,384	(6,294)
Operating expenses:
Research and development	8,933	8,427	16,306	17,075
Selling, general and administrative	13,627	12,241	22,951	20,550
Total operating expenses	22,560	20,668	39,257	37,625
Operating loss	(12,406)	(22,978)	(35,873)	(43,919)
Interest and other expense, net	(7,861)	(6,136)	(16,206)	(9,241)
Change in fair value of common stock warrant liability	1,706	334	(420)	1,592
Loss before income taxes	(18,561)	(28,780)	(52,499)	(51,568)
Income tax benefit		2,912		5,865
Net loss attributable to the Company	(18,561)	(25,868)	(52,499)	(45,703)
Preferred stock dividends declared and accretion of discount	(26)	(13)	(26)	(26)
Net loss attributable to common shareholders	$ (18,587)	$ (25,881)	$ (52,525)	$ (45,729)
Net loss per share:
Basic and diluted	$ (0.08)	$ (0.12)	$ (0.23)	$ (0.21)
Weighted average number of common shares outstanding	231,114,868	214,315,312	225,899,224	220,650,537
Sales of fuel cell systems and related infrastructure
Net revenue:
Net revenue	$ 38,547	$ 18,820	$ 40,767	$ 29,433
Cost of revenue:
Total cost of revenue	23,129	15,377	25,450	25,499
Services performed on fuel cell systems and related infrastructure
Net revenue:
Net revenue	5,282	5,691	11,495	11,174
Cost of revenue:
Total cost of revenue	6,218	6,103	12,341	11,837
Power Purchase Agreements
Net revenue:
Net revenue	6,307	5,438	11,014	10,810
Cost of revenue:
Total cost of revenue	8,713	9,638	17,711	18,288
Fuel delivered to customers
Net revenue:
Net revenue	6,932	5,280	12,385	10,230
Cost of revenue:
Total cost of revenue	$ 8,854	$ 6,421	$ 16,775	$ 12,317