CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net revenue:
Net revenue	$ (309,099)	$ 107,048	$ 67,995	$ 40,819	$ 91,607	$ 59,392	$ 57,466	$ 21,510	$ 108,814	$ 78,976	$ 215,862	$ 138,368	$ (93,237)	$ 229,975	$ 174,215
Cost of revenue:
Provision (benefit) for loss contracts related to service		135,632	68,010	50,522	83,861	54,892	51,324	29,250	118,532	80,574	254,164	135,466	376,179	219,327	200,219
Gross (loss) profit	(431,114)	(28,584)	(15)	(9,703)	7,746	4,500	6,142	(7,740)	(9,718)	(1,598)	(38,302)	2,902	(469,416)	10,648	(26,004)
Operating expenses:
Research and development		7,386	4,873	4,774	4,882	3,563	3,608	3,006	9,647	6,614	17,033	10,177	27,848	15,059	12,750
Selling, general and administrative		17,210	21,644	11,109	9,973	10,395	13,613	9,221	32,753	22,834	49,963	33,229	79,348	43,202	37,685
Impairment of long-lived assets													6,430
Change in fair value of contingent consideration		1,130									1,130		1,160
Total operating expenses	46,660	25,726	26,517	15,883	14,855	13,958	17,221	12,227	42,400	29,448	68,126	43,406	114,786	58,261	50,435
Operating loss	(477,774)	(54,310)	(26,532)	(25,586)	(7,109)	(9,458)	(11,079)	(19,967)	(52,118)	(31,046)	(106,428)	(40,504)	(584,202)	(47,613)	(76,439)
Interest and other expense, net		(17,551)	(13,462)	(11,846)	(10,999)	(8,273)	(7,965)	(8,454)	(25,308)	(16,419)	(42,859)	(24,692)	(60,484)	(35,691)	(22,750)
Gain (loss) on extinguishment of debt			13,222			(518)		(518)	13,222	(518)	13,222	(518)	17,686	(518)
Change in fair value of common stock warrant liability					72	427	1,706	(2,126)		(420)		7		79	4,286
Loss before income taxes		(71,861)	(26,772)	(37,432)	(18,036)	(17,822)	(17,338)	(30,547)	(64,204)	(47,885)	(136,065)	(65,707)	(627,000)	(83,743)	(94,903)
Income tax benefit		6,644	17,371						17,371		24,015		30,845		9,295
Net loss attributable to the Company		(65,217)	(9,401)	(37,432)	(18,036)	(17,822)	(17,338)	(30,547)	(46,833)	(47,885)	(112,050)	(65,707)	(596,155)	(83,743)	(85,608)
Preferred stock dividends declared, deemed dividends and accretion of discount			(13)	(13)	(1,241)	(544)	(13)	(13)	(26)	(26)	(26)	(570)	(26)	(1,812)	(52)
Net loss attributable to common stockholders	$ (484,105)	$ (65,217)	$ (9,414)	$ (37,445)	$ (19,277)	$ (18,366)	$ (17,351)	$ (30,560)	$ (46,859)	$ (47,911)	$ (112,076)	$ (66,277)	$ (596,181)	$ (85,555)	$ (85,660)
Net loss per share:
Net loss per share, basic	$ (1.35)	$ (0.18)	$ (0.03)	$ (0.12)	$ (0.07)	$ (0.08)	$ (0.08)	$ (0.14)	$ (0.15)	$ (0.21)	$ (0.34)	$ (0.29)	$ (1.68)	$ (0.36)	$ (0.39)
Net loss per share, diluted	$ (1.35)	$ (0.18)	$ (0.03)	$ (0.12)	$ (0.07)	$ (0.08)	$ (0.08)	$ (0.14)	$ (0.15)	$ (0.21)	$ (0.34)	$ (0.29)	$ (1.68)	$ (0.36)	$ (0.39)
Weighted average number of common stock outstanding, basic		371,010,544	316,645,050	305,192,201	260,053,150	236,759,521	231,114,868	220,605,068	310,918,626	225,899,224	330,949,265	229,519,323	354,790,106	237,152,780	218,882,337
Weighted average number of common stock outstanding, diluted		371,010,544	316,645,050	305,192,201	260,053,150	236,759,521	231,114,868	220,605,068	310,918,626	225,899,224	330,949,265	229,519,323	354,790,106	237,152,780	218,882,337
Sales of fuel cell systems, related infrastructure and equipment
Net revenue:
Net revenue	$ (246,171)	$ 83,662	$ 47,746	$ 20,468	$ 69,785	$ 38,883	$ 38,702	$ 2,550	$ 68,214	$ 41,252	$ 151,876	$ 80,135	$ (94,295)	$ 149,920	$ 107,175
Cost of revenue:
Provision (benefit) for loss contracts related to service		69,428	33,888	13,974	47,091	25,183	23,329	2,312	47,862	25,641	117,290	50,824	171,404	97,915	85,205
Services performed on fuel cell systems and related infrastructure
Net revenue:
Net revenue	(29,387)	6,829	6,236	6,521	7,328	6,205	5,341	6,343	12,757	11,684	19,586	17,889	(9,801)	25,217	22,002
Cost of revenue:
Provision (benefit) for loss contracts related to service		9,180	7,773	10,347	11,606	7,802	8,383	6,791	18,120	15,174	27,300	22,976	42,524	34,582	32,271
Provision (benefit) for loss contracts related to service
Cost of revenue:
Provision (benefit) for loss contracts related to service		25,147	706	95	13	206	363	162	801	201	25,948	407	35,473	394	5,345
Power Purchase Agreements
Net revenue:
Net revenue	6,991	6,629	6,579	6,421	6,664	6,520	6,334	6,035	13,000	12,369	19,629	18,889	26,620	25,553	22,569
Cost of revenue:
Provision (benefit) for loss contracts related to service		14,744	14,504	14,771	12,301	10,814	8,829	9,833	29,275	18,662	44,019	29,476	64,640	41,777	41,361
Fuel delivered to customers
Net revenue:
Net revenue	(40,608)	9,831	7,372	7,333	7,779	7,649	7,089	6,582	14,705	13,671	24,536	21,320	(16,072)	29,099	22,469
Cost of revenue:
Provision (benefit) for loss contracts related to service		17,002	11,076	11,254	12,800	11,149	$ 11,146	$ 10,152	22,330	$ 21,298	39,332	32,447	61,815	45,247	$ 36,037
Other
Net revenue:
Net revenue	$ 76	97	62	76	51	135			138		235	135	311	186
Cost of revenue:
Provision (benefit) for loss contracts related to service		$ 131	$ 63	$ 81	$ 50	$ 150			$ 144		$ 275	$ 150	$ 323	$ 200