Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 213,543	$ 224,307	$ 200,326	$ 147,001	$ 157,145	$ 168,619	$ 138,302	$ 168,582	$ 347,327	$ 306,884	$ 571,634	$ 475,503	$ 785,177	$ 632,648	$ 365,623
Cost of revenue	188,595	181,582	171,976	145,437	150,224	141,209	111,318	124,147	317,413	235,465	498,995	376,674	687,590	526,898	381,934
Gross profit (loss)	24,948	42,725	28,350	1,564	6,921	27,410	26,984	44,435	29,914	71,419	72,639	98,829	97,587	105,750	(16,311)
Operating expenses:
Research and development	22,148	23,389	29,772	28,859	32,970	27,021	14,413	14,731	58,631	29,144	82,020	56,165	104,168	89,135	51,146
Sales and marketing	17,357	17,649	18,194	20,373	24,951	21,396	8,167	8,293	38,567	16,460	56,216	37,856	73,573	62,807	31,926
General and administrative	33,315	36,599	43,662	39,074	47,471	40,999	15,359	14,988	82,736	30,347	119,335	71,346	152,650	118,817	55,689
Total operating expenses	72,820	77,637	91,628	88,306	105,392	89,416	37,939	38,012	179,934	75,951	257,571	165,367	330,391	270,759	138,761
Loss from operations	(47,872)	(34,912)	(63,278)	(86,742)	(98,471)	(62,006)	(10,955)	6,423	(150,020)	(4,532)	(184,932)	(66,538)	(232,804)	(165,009)	(155,072)
Interest income	862	1,214	1,700	1,885	1,996	1,467	444	415	3,585	859	4,799	2,326	5,661	4,322	759
Interest expense	(21,635)	(21,323)	(22,722)	(21,800)	(21,757)	(22,125)	(27,147)	(25,992)	(44,522)	(53,139)	(65,845)	(75,264)	(87,480)	(97,021)	(112,039)
Interest expense to related parties	(1,933)	(1,605)	(1,606)	(1,612)	(1,628)	(1,966)	(2,672)	(2,627)	(3,218)	(5,299)	(4,823)	(7,265)	(6,756)	(8,893)	(12,265)
Other income (expense), net	138	525	(222)	265	636	(705)	(855)	(75)	43	(930)	568	(1,635)	706	(999)	(491)
Gain (loss) on revaluation of warrant liabilities and embedded derivatives	(540)	(540)	(540)	(540)	192	900	(19,197)	(4,034)	(1,080)	(23,231)	(1,620)	(22,331)	(2,160)	(22,139)	(15,284)
Loss before income taxes	(70,980)	(56,641)	(86,668)	(108,544)	(119,032)	(84,435)	(60,382)	(25,890)	(195,212)	(86,272)	(251,853)	(170,707)	(322,833)	(289,739)	(294,392)
Income tax provision	31	136	258	208	1,079	(3)	128	333	466	461	602	458	633	1,537	636
Net loss	(71,011)	(56,777)	(86,926)	(108,752)	(120,111)	(84,432)	(60,510)	(26,223)	(195,678)	(86,733)	(252,455)	(171,165)	(323,466)	(291,276)	(295,028)
Less: net loss attributable to noncontrolling interests and redeemable noncontrolling interests	(5,178)	(5,027)	(5,015)	(3,832)	(4,662)	(3,930)	(4,512)	(4,632)	(8,847)	(9,144)	(13,874)	(13,074)	(19,052)	(17,736)	(18,666)
Net loss available to Class A and Class B common stockholders	(65,833)	(51,750)	(81,911)	(104,920)	(115,449)	(80,502)	(55,998)	(21,591)	(186,831)	(77,589)	(238,581)	(158,091)	(304,414)	(273,540)	(276,362)
Less: deemed dividend to noncontrolling interest	(2,454)	0	0	0	0	0	0	0					(2,454)	0	0
Net loss available to Class A and Class B common stockholders	$ (68,287)	$ (51,750)	$ (81,911)	$ (104,920)	$ (115,449)	$ (80,502)	$ (55,998)	$ (21,591)					$ (306,868)	$ (273,540)	$ (276,362)
Net loss per share attributable to Class A and Class B common stockholders, basic and diluted (in dollars per share)	$ (0.58)	$ (0.44)	$ (0.72)	$ (0.94)	$ (1.06)	$ (0.99)	$ (5.31)	$ (2.08)					$ (2.67)	$ (5.14)	$ (26.97)
Weighted average shares used to compute net loss per share attributable to Class A and Class B common stockholders, basic and diluted (in shares)	118,588	116,330	113,624	111,842	109,416	81,321	10,536	10,404					115,118	53,268	10,248
Product
Revenue	$ 158,427	$ 163,902	$ 144,081	$ 90,926	$ 103,937	$ 102,433	$ 78,497	$ 115,771	235,007	194,268	398,909	296,701	$ 557,336	$ 400,638	$ 157,192
Cost of revenue	141,782	91,697	113,228	88,772	86,154	69,053	49,603	76,465	202,000	126,068	293,697	195,121	435,479	281,275	192,361
Installation
Revenue	14,429	21,102	13,076	12,219	11,066	24,691	19,643	12,795	25,295	32,438	46,397	57,129	60,826	68,195	57,937
Cost of revenue	16,901	26,141	17,685	15,760	20,651	35,506	29,951	9,198	33,445	39,149	59,586	74,655	76,487	95,306	54,970
Service
Revenue	25,628	23,665	23,026	23,467	21,778	21,056	20,299	20,134	46,493	40,433	70,158	61,489	95,786	83,267	74,892
Cost of revenue	17,127	36,427	18,763	27,921	31,818	24,470	19,702	24,699	46,684	44,401	83,111	68,871	100,238	100,689	85,128
Electricity
Revenue	15,059	15,638	20,143	20,389	20,364	20,439	19,863	19,882	40,532	39,745	56,170	60,184	71,229	80,548	75,602
Cost of revenue	$ 12,785	$ 27,317	$ 22,300	$ 12,984	$ 11,601	$ 12,180	$ 12,062	$ 13,785	$ 35,284	$ 25,847	$ 62,601	$ 38,027	$ 75,386	$ 49,628	$ 49,475