Unaudited Quarterly Financial data and Restatement of Previously Issued Unaudited Interim Condensed Consolidated Financial Statements - Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,312,404	$ 448,140	$ 152,492	$ 74,340	$ 139,496	$ 43,275	$ 19,845	$ 39,336
Restricted cash	64,041	55,704	50,634	56,804	54,813	35,720	19,400	19,297
Accounts receivable	43,041	113,505	45,782	24,734	25,768	24,737	26,844	32,307
Inventory	139,386	134,203	114,571	92,972	72,391	80,601	73,190	65,474
Prepaid expenses and other current assets	44,324	26,731	31,436	28,500	21,192	12,804	14,001	10,296
Total current assets	1,603,196	778,283	394,915	277,350	313,660	197,137	153,280	166,710
Restricted cash	257,839	227,528	180,127	176,070	175,191	119,322	96,082	50,598
Property, plant, and equipment, net	74,549	64,820	60,018	16,591	14,959	14,990	14,228	13,615
Right of use assets related to finance leases, net	5,724	2,335	2,389	1,707	1,714	1,720	1,726	1,733
Right of use assets related to operating leases, net	117,016	90,184	71,789	64,812	63,266	47,016	39,679	33,599
Equipment related to power purchase agreements and fuel delivered to customers, net	75,807	71,891	68,428	68,402	67,769	67,248	68,982	70,928
Goodwill	72,387	71,822	70,262	8,673	8,842	8,606	8,961	8,886
Intangible assets, net	39,251	39,569	38,974	5,696	5,539	5,113	5,398	3,677
Other assets	5,513	9,661	11,817	12,059	8,573	9,152	8,842	11,069
Total assets	2,251,282	1,356,093	898,719	631,360	659,513	470,304	397,178	360,815
Current liabilities:
Accounts payable	50,198	58,793	39,812	35,503	40,376	36,851	36,946	31,688
Accrued expenses	46,083	37,948	23,917	14,870	14,409	9,457	4,522	6,509
Deferred revenue.	23,275	17,226	14,902	11,557	11,691	11,480	11,730	11,736
Operating lease liabilities	14,314	10,609	9,453	8,959	9,428	8,666	7,512	7,042
Finance lease liabilities	903	374	345	204	226	310	266	236
Finance obligations	32,717	31,349	28,794	26,209	24,667	20,469	12,455	11,028
Current portion of long-term debt	25,389	74,829	50,933	27,819	26,461	17,202	15,928	12,559
Other current liabilities	29,487	21,083	19,418	8,446	6,704	8,373	3,705	3,745
Total current liabilities	222,366	252,211	187,574	133,567	133,962	112,808	93,064	84,543
Deferred revenue	32,944	29,511	24,848	22,684	23,170	22,213	24,126	25,366
Operating lease liabilities	99,624	74,422	58,410	52,165	50,937	36,599	30,631	25,657
Finance lease liabilities	4,493	2,384	2,465	1,953	2,011	2,068	2,123	2,142
Common stock warrant liability						98	525	2,231
Finance obligations	148,836	140,662	131,653	121,322	119,422	99,669	76,916	54,864
Convertible senior notes, net	85,640	105,088	142,889	113,063	110,431	107,945	66,844	65,025
Long-term debt	150,013	120,380	101,844	79,119	85,708	78,840	83,776	72,676
Other liabilities	40,447	45,170	14,476	2,386	2,818	2,834	3,333	3,746
Total liabilities	784,363	769,828	664,159	526,259	528,459	463,074	381,338	336,250
Stockholders' equity:
Common stock, $.01 par value	4,740	4,061	3,482	3,222	3,186	2,540	2,470	2,445
Additional paid-in capital	3,446,650	2,083,169	1,658,438	1,519,094	1,506,953	1,340,781	1,325,381	1,316,815
Accumulated other comprehensive income	2,451	1,846	1,159	1,052	1,288	929	1,460	1,374
Accumulated deficit	(1,946,488)	(1,462,377)	(1,397,160)	(1,387,752)	(1,350,307)	(1,332,259)	(1,314,425)	(1,297,072)
Less common stock in treasury	(40,434)	(40,434)	(31,359)	(31,224)	(31,216)	(31,216)	(30,681)	(30,637)
Total stockholders' equity	1,466,919	586,265	234,560	104,392	129,904	(19,225)	(15,795)	(7,075)	$ (3,588)	$ 70,229
Total liabilities, redeemable preferred stock, and stockholders' equity	$ 2,251,282	1,356,093	898,719	631,360	659,513	470,304	397,178	360,815
As previously Reported
Current assets:
Cash and cash equivalents		448,140	152,492	74,340	139,496	43,275	19,845	39,336
Restricted cash		55,704	50,634	56,804	54,813	35,720	19,400	19,297
Accounts receivable		113,133	45,522	24,437	25,448	24,392	26,592	32,062
Inventory		134,306	114,571	92,972	72,391	80,601	73,190	65,474
Prepaid expenses and other current assets		26,731	31,436	28,500	21,192	12,804	14,001	10,296
Total current assets		778,014	394,655	277,053	313,340	196,792	153,028	166,465
Restricted cash		227,528	180,127	176,070	175,191	119,322	96,082	50,598
Property, plant, and equipment, net		64,820	60,018	16,591	14,959	14,990	14,228	13,615
Equipment related to power purchase agreements and fuel delivered to customers, net		309,475	274,721	252,802	244,740	202,034	170,455	141,889
Goodwill		71,962	70,402	8,673	8,842	8,606	8,961	8,886
Intangible assets, net		39,169	38,574	5,296	5,539	5,113	5,398	3,677
Other assets		9,661	11,817	12,059	8,573	9,152	8,842	11,069
Total assets		1,500,629	1,030,314	748,544	771,184	556,009	456,994	396,199
Current liabilities:
Accounts payable		58,793	39,812	35,503	40,376	36,851	36,946	31,688
Accrued expenses		32,031	23,320	14,273	14,213	9,457	4,522	6,509
Deferred revenue.		17,226	14,902	11,557	11,691	11,480	11,730	11,736
Finance obligations		63,692	57,695	52,047	49,507	41,112	30,663	23,997
Current portion of long-term debt		74,829	50,933	27,819	26,461	17,202	15,928	12,559
Other current liabilities		17,280	21,692	10,423	8,543	10,238	3,017	2,271
Total current liabilities		263,851	208,354	151,622	150,791	126,340	102,806	88,760
Deferred revenue		29,648	25,038	22,912	23,369	22,444	24,519	25,835
Common stock warrant liability						98	525	2,231
Finance obligations		337,150	300,653	272,171	265,228	208,465	157,531	111,195
Convertible senior notes, net		105,088	142,704	112,878	110,246	107,760	66,844	65,025
Long-term debt		120,380	101,844	79,119	85,708	78,840	83,776	72,676
Other liabilities		27,068	11,756	13	13	13	13	17
Total liabilities		883,185	790,349	638,715	635,355	543,960	436,014	365,739
Stockholders' equity:
Common stock, $.01 par value		4,061	3,482	3,222	3,186	2,540	2,470	2,445
Additional paid-in capital		2,083,199	1,658,532	1,519,257	1,507,116	1,340,859	1,325,459	1,316,893
Accumulated other comprehensive income		1,958	1,271	1,164	1,400	929	1,460	1,374
Accumulated deficit		(1,431,340)	(1,391,961)	(1,383,299)	(1,345,807)	(1,327,518)	(1,309,363)	(1,291,255)
Less common stock in treasury		(40,434)	(31,359)	(31,224)	(31,216)	(31,216)	(30,681)	(30,637)
Total stockholders' equity		617,444	239,965	109,120	134,679	(14,406)	(10,655)	(1,180)	134,679	2,713	$ 73,646
Total liabilities, redeemable preferred stock, and stockholders' equity		1,500,629	1,030,314	748,544	771,184	556,009	456,994	396,199
Restatement Adjustments
Current assets:
Accounts receivable		372	260	297	320	345	252	245
Inventory		(103)
Total current assets		269	260	297	320	345	252	245
Right of use assets related to finance leases, net		2,335	2,389	1,707	1,714	1,720	1,726	1,733
Right of use assets related to operating leases, net		90,184	71,789	64,812	63,266	47,016	39,679	33,599
Equipment related to power purchase agreements and fuel delivered to customers, net		(237,584)	(206,293)	(184,400)	(176,971)	(134,786)	(101,473)	(70,961)
Goodwill		(140)	(140)
Intangible assets, net		400	400	400
Total assets		(144,536)	(131,595)	(117,184)	(111,671)	(85,705)	(59,816)	(35,384)
Current liabilities:
Accrued expenses		5,917	597	597	196
Operating lease liabilities		10,609	9,453	8,959	9,428	8,666	7,512	7,042
Finance lease liabilities		374	345	204	226	310	266	236
Finance obligations		(32,343)	(28,901)	(25,838)	(24,840)	(20,643)	(18,208)	(12,969)
Other current liabilities		3,803	(2,274)	(1,977)	(1,839)	(1,865)	688	1,474
Total current liabilities		(11,640)	(20,780)	(18,055)	(16,829)	(13,532)	(9,742)	(4,217)
Deferred revenue		(137)	(190)	(228)	(199)	(231)	(393)	(469)
Operating lease liabilities		74,422	58,410	52,165	50,937	36,599	30,631	25,657
Finance lease liabilities		2,384	2,465	1,953	2,011	2,068	2,123	2,142
Finance obligations		(196,488)	(169,000)	(150,849)	(145,806)	(108,796)	(80,615)	(56,331)
Convertible senior notes, net			185	185	185	185
Other liabilities		18,102	2,720	2,373	2,805	2,821	3,320	3,729
Total liabilities		(113,357)	(126,190)	(112,456)	(106,896)	(80,886)	(54,676)	(29,489)
Stockholders' equity:
Additional paid-in capital		(30)	(94)	(163)	(163)	(78)	(78)	(78)
Accumulated other comprehensive income		(112)	(112)	(112)	(112)
Accumulated deficit		(31,037)	(5,199)	(4,453)	(4,500)	(4,741)	(5,062)	(5,817)
Total stockholders' equity		(31,179)	(5,405)	(4,728)	(4,775)	(4,819)	(5,140)	(5,895)	(6,301)	$ (3,417)
Total liabilities, redeemable preferred stock, and stockholders' equity		(144,536)	(131,595)	(117,184)	(111,671)	(85,705)	(59,816)	(35,384)
Other Adjustments
Current assets:
Accounts receivable		372	260	297	320	345	252	245
Inventory		103
Goodwill		140	(140)
Intangible assets, net		400	400	400
Current liabilities:
Accrued expenses		703	597	597	196
Deferred revenue		137	(190)	(228)	199	(231)	(393)	(469)
Convertible senior notes, net			185	185	185	185
Stockholders' equity:
Additional paid-in capital		30	(94)	(163)	163	78	(78)	(78)	$ 78
Accumulated other comprehensive income		$ 112	$ (112)	(112)	112
Series C Redeemable Convertible Preferred Stock
Redeemable preferred stock:
Preferred stock				709	709	709	709	709
Series C Redeemable Convertible Preferred Stock | As previously Reported
Redeemable preferred stock:
Preferred stock				$ 709	709	709	709	709
Series E Redeemable Convertible Preferred Stock
Redeemable preferred stock:
Preferred stock					441	25,746	30,926	30,931
Series E Redeemable Convertible Preferred Stock | As previously Reported
Redeemable preferred stock:
Preferred stock					$ 441	$ 25,746	$ 30,926	$ 30,931