Restatement of Previously Issued Consolidated Financial Statements - Consolidated Statements of Cash Flows (Details) - USD ($)	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
Cash flows from operating activities:
Net income (loss)	$ (71,011,000)	$ (56,777,000)	$ (86,926,000)	$ (108,752,000)	$ (120,111,000)	$ (84,432,000)	$ (60,510,000)	$ (26,223,000)	$ (195,678,000)	$ (86,733,000)	$ (252,455,000)	$ (171,165,000)	$ (323,466,000)	$ (291,276,000)	$ (295,028,000)
Depreciation and amortization				14,225,000				13,304,000	37,034,000	26,466,000	64,948,000	39,757,000	78,584,000	53,887,000	54,376,000
Write-off of property, plant and equipment, net				1,000					2,704,000	661,000	2,987,000	901,000	3,117,000	939,000	48,000
Write-off of customer financing receivable													11,302,000	0	0
Write-off of PPA II and PPA IIIb decommissioned assets									25,613,000		25,613,000		70,543,000	0	0
Revaluation of derivative contracts				87,000				7,157,000	1,636,000	28,611,000	2,955,000	27,516,000	2,779,000	29,021,000	15,042,000
Stock-based compensation				67,822,000				8,147,000	119,186,000	15,481,000	160,233,000	76,674,000	196,291,000	168,482,000	29,101,000
Loss (gain) on long-term REC purchase contract				59,000				12,000	60,000	100,000	61,000	150,000	53,000	200,000	(70,000)
Revaluation of stock warrants								(100,000)		(7,456,000)		(9,109,000)	0	(9,108,000)	(2,975,000)
Debt make-whole expense									5,934,000		5,934,000		5,934,000	0	0
Amortization of debt issuance cost				5,152,000				7,168,000	11,255,000	14,420,000	16,295,000	20,279,000	22,130,000	25,437,000	47,312,000
Accounts receivable				4,131,000				(28,235,000)	49,741,000	(6,681,000)	63,426,000	(11,500,000)	51,952,000	(55,023,000)	3,242,000
Inventories				11,087,000				(3,527,000)	22,197,000	(38,257,000)	(1,775,000)	(40,428,000)	18,425,000	(36,974,000)	(10,636,000)
Deferred cost of revenue				(11,084,000)				12,741,000	(38,793,000)	20,398,000	(2,344,000)	13,602,000	(21,992,000)	14,223,000	(31,278,000)
Customer financing receivable and other				1,339,000				1,306,000	2,713,000	2,439,000	4,142,000	3,736,000	5,520,000	4,878,000	5,459,000
Prepaid expenses and other current assets				6,628,000				483,000	10,227,000	4,764,000	8,071,000	(8,099,000)	8,643,000	(8,032,000)	(982,000)
Other long-term assets				(416,000)				848,000	(272,000)	(851,000)	1,294,000	(346,000)	3,618,000	(202,000)	756,000
Accounts payable				(2,464,000)				(827,000)	(5,461,000)	5,217,000	14,171,000	11,236,000	(11,310,000)	18,307,000	7,076,000
Accrued warranty				(2,697,000)				(77,000)	(6,696,000)	(2,183,000)	(4,074,000)	840,000	(6,603,000)	1,498,000	(7,365,000)
Accrued expenses and other current liabilities				(373,000)				(10,598,000)	5,581,000	(14,201,000)	5,191,000	2,511,000	6,728,000	(5,984,000)	7,997,000
Deferred revenue and customer deposits				1,244,000				(15,727,000)	51,913,000	(22,030,000)	22,252,000	(14,772,000)	37,146,000	(21,774,000)	48,322,000
Other long-term liabilities				4,166,000				9,030,000	4,722,000	19,149,000	4,560,000	11,518,000	4,376,000	19,553,000	37,637,000
Net cash provided by (used in) operating activities				(9,845,000)				(28,389,000)	103,616,000	(40,852,000)	141,485,000	(46,699,000)	163,770,000	(91,948,000)	(91,966,000)
Cash flows from investing activities:
Purchase of property, plant and equipment				(11,946,000)				(4,858,000)	(23,619,000)	(13,145,000)	(39,690,000)	(24,616,000)	(51,053,000)	(45,205,000)	(61,454,000)
Payments for acquisition of intangible assets				(848,000)					(970,000)		(1,478,000)	(2,762,000)	0	(3,256,000)	0
Purchase of marketable securities								(8,991,000)		(15,732,000)		(15,732,000)	0	(103,914,000)	(29,043,000)
Proceeds from maturity of marketable securities				104,500,000				15,750,000	104,500,000	27,000,000	104,500,000	38,250,000	104,500,000	27,000,000	2,250,000
Net cash provided by (used in) investing activities				91,706,000				1,901,000	79,911,000	(1,877,000)	63,332,000	(4,860,000)	53,447,000	(125,375,000)	(88,247,000)
Cash flows from financing activities:
Borrowings from issuance of debt													0	0	100,000,000
Repayment of debt				(5,016,000)				(4,489,000)	(83,997,000)	(9,201,000)	(93,263,000)	(14,036,000)	(119,277,000)	(18,770,000)	(20,507,000)
Repayment of debt to related parties				(778,000)				(290,000)	(1,220,000)	(627,000)	(1,691,000)	(990,000)	(2,200,000)	(1,390,000)	(912,000)
Debt make-whole payment									(5,934,000)		(5,934,000)		(5,934,000)	0	0
Debt issuance costs													0	0	(6,108,000)
Proceeds from financing obligations				10,961,000					20,333,000	36,799,000	20,333,000	57,897,000	72,334,000	70,265,000	84,314,000
Repayment of financing obligations				(1,883,000)				1,463,000	(4,006,000)	2,982,000	(6,419,000)	(4,563,000)	(8,954,000)	(6,188,000)	(3,210,000)
Proceeds from noncontrolling and redeemable noncontrolling interests													0	0	13,652,000
Payments to noncontrolling and redeemable noncontrolling interests									(18,690,000)		(43,713,000)		(56,459,000)	0	0
Distributions to noncontrolling and redeemable noncontrolling interests				(3,189,000)				(3,832,000)	(7,753,000)	(11,582,000)	(9,363,000)	(14,192,000)	(12,537,000)	(15,250,000)	(23,659,000)
Proceeds from issuance of common stock				7,493,000				120,000	8,321,000	742,000	12,623,000	1,456,000	12,713,000	1,521,000	432,000
Proceeds from public offerings, net of underwriting discounts and commissions												292,529,000	0	292,529,000	0
Payments of initial public offering issuance costs								(578,000)		(1,160,000)		(2,928,000)	0	(5,521,000)	(1,092,000)
Net cash provided by (used in) financing activities				7,588,000				(10,532,000)	(92,946,000)	11,989,000	(127,427,000)	315,173,000	(120,314,000)	317,196,000	142,910,000
Net increase (decrease) in cash, cash equivalents, and restricted cash				89,449,000				(37,020,000)	90,581,000	(30,740,000)	77,390,000	263,614,000	96,903,000	99,873,000	(37,303,000)
Beginning of period	357,875,000	371,066,000	369,934,000	280,485,000	444,226,000	149,872,000	143,592,000	180,612,000	280,485,000	180,612,000	280,485,000	180,612,000	280,485,000	180,612,000	217,915,000
End of period	377,388,000	357,875,000	371,066,000	369,934,000	280,485,000	444,226,000	149,872,000	143,592,000	371,066,000	149,872,000	357,875,000	444,226,000	377,388,000	280,485,000	180,612,000
Supplemental disclosure of cash flow information:
Cash paid during the period for interest				20,383,000				15,829,000	35,702,000	25,773,000	53,772,000	45,106,000	69,851,000	59,549,000	37,628,000
Cash paid during the period for taxes				222,000				401,000	497,000	625,000	715,000	1,052,000	860,000	1,748,000	616,000
Liabilities recorded for property, plant and equipment													1,745,000	12,236,000	975,000
Liabilities recorded for intangible assets													0	3,180,000	2,138,000
Issuance of common stock warrant													0	0	9,410,000
Reclassification of redeemable convertible preferred stock warrant liability to additional paid-in capital													0	882,000	0
Conversion of redeemable convertible preferred stock into additional paid-in capital													0	1,465,841,000	0
Conversion of 8% convertible promissory notes into additional paid-in capital													0	181,469,000	0
Reclassification of derivative liability into additional paid-in capital													0	177,208,000	0
Reclassification of prior year prepaid initial public offering costs to additional paid-in capital													0	4,732,000	0
Issuance of common stock													0	0	1,981,000
Issuance of restricted stock													0	0	1,254,000
Accrued distributions to Equity Investors													373,000	576,000	576,000
Accrued interest for notes													1,812,000	19,041,000	29,705,000
Accrued interest for notes to related parties													0	2,733,000	4,368,000
Previously Reported
Cash flows from operating activities:
Net income (loss)		(39,930,000)	(67,231,000)	(88,273,000)	(104,443,000)	(82,510,000)	(50,188,000)	(22,348,000)	(155,504,000)	(72,536,000)	(195,434,000)	(155,046,000)		(259,489,000)	(281,265,000)
Depreciation and amortization				11,271,000				10,847,000	31,023,000	21,554,000	55,816,000	32,141,000		43,459,000	46,105,000
Write-off of property, plant and equipment, net				1,000					2,704,000	661,000	2,987,000	901,000		939,000	48,000
Write-off of PPA II and PPA IIIb decommissioned assets									25,613,000		25,613,000
Revaluation of derivative contracts				(453,000)				7,157,000	555,000	28,611,000	1,335,000	26,761,000		28,471,000	14,754,000
Stock-based compensation				63,882,000				7,956,000	115,100,000	15,773,000	154,955,000	87,451,000		180,284,000	30,479,000
Loss (gain) on long-term REC purchase contract				59,000				12,000	60,000	100,000	61,000	150,000		200,000	(70,000)
Revaluation of stock warrants								(100,000)		(7,456,000)		(9,109,000)		(9,108,000)	(2,975,000)
Debt make-whole expense									5,934,000		5,934,000
Amortization of debt issuance cost				5,152,000				7,168,000	11,255,000	14,420,000	16,295,000	20,279,000		25,437,000	47,312,000
Accounts receivable				816,000				(28,203,000)	46,591,000	(6,486,000)	58,150,000	(11,168,000)		(54,570,000)	4,849,000
Inventories				15,932,000				(6,818,000)	27,542,000	(46,172,000)	(7,896,000)	(44,465,000)		(42,216,000)	(7,105,000)
Deferred cost of revenue				26,014,000				16,282,000	19,198,000	48,760,000	56,854,000	47,945,000		88,324,000	(70,979,000)
Customer financing receivable and other				1,339,000				1,306,000	2,713,000	2,439,000	4,142,000	3,736,000		4,878,000	5,459,000
Prepaid expenses and other current assets				5,194,000				(446,000)	8,477,000	4,544,000	7,928,000	(6,514,000)		(7,064,000)	(2,175,000)
Other long-term assets				83,000				1,266,000	1,028,000	15,000	3,281,000	1,052,000		1,897,000	4,625,000
Accounts payable				(2,464,000)				(827,000)	(5,461,000)	5,217,000	14,171,000	11,236,000		18,307,000	7,076,000
Accrued warranty				(2,500,000)				(87,000)	(6,843,000)	(1,883,000)	(3,941,000)	1,164,000		2,426,000	(7,045,000)
Accrued expenses and other current liabilities				823,000				(10,083,000)	7,213,000	(12,815,000)	5,029,000	1,885,000		(6,800,000)	8,599,000
Deferred revenue and customer deposits				(44,533,000)				(22,347,000)	(25,411,000)	(31,817,000)	(68,180,000)	(32,203,000)		(91,996,000)	91,893,000
Other long-term liabilities				3,487,000				8,049,000	3,419,000	18,652,000	2,083,000	10,156,000		18,204,000	43,239,000
Net cash provided by (used in) operating activities				(4,170,000)				(34,487,000)	115,206,000	(18,585,000)	139,183,000	(13,648,000)		(58,417,000)	(67,176,000)
Cash flows from investing activities:
Purchase of property, plant and equipment				(8,543,000)				(223,000)	(18,882,000)	(1,595,000)	(23,474,000)	(4,333,000)		(14,659,000)	(5,140,000)
Payments for acquisition of intangible assets				(848,000)					(970,000)		(1,478,000)	(2,762,000)		(3,256,000)
Purchase of marketable securities								(8,991,000)		(15,732,000)		(15,732,000)		(103,914,000)	(29,043,000)
Proceeds from maturity of marketable securities				104,500,000				15,750,000	104,500,000	27,000,000	104,500,000	38,250,000		27,000,000	2,250,000
Net cash provided by (used in) investing activities				95,109,000				6,536,000	84,648,000	9,673,000	79,548,000	15,423,000		(94,829,000)	(31,933,000)
Cash flows from financing activities:
Borrowings from issuance of debt															100,000,000
Repayment of debt				(5,016,000)				(4,489,000)	(83,997,000)	(9,201,000)	(93,263,000)	(14,036,000)		(18,770,000)	(20,507,000)
Repayment of debt to related parties				(778,000)				(290,000)	(1,220,000)	(627,000)	(1,691,000)	(990,000)		(1,390,000)	(912,000)
Debt make-whole payment									(5,934,000)		(5,934,000)
Debt issuance costs															(6,108,000)
Proceeds from financing obligations				0					0	0	0	0		0	0
Repayment of financing obligations				0				0	0	0	0	0		0	0
Proceeds from noncontrolling and redeemable noncontrolling interests															13,652,000
Payments to noncontrolling and redeemable noncontrolling interests									(18,690,000)		(43,713,000)
Distributions to noncontrolling and redeemable noncontrolling interests				(3,189,000)				(3,832,000)	(7,753,000)	(11,582,000)	(9,363,000)	(14,192,000)		(15,250,000)	(23,659,000)
Proceeds from issuance of common stock				7,493,000				120,000	8,321,000	742,000	12,623,000	1,456,000		1,521,000	432,000
Proceeds from public offerings, net of underwriting discounts and commissions												292,529,000		292,529,000
Payments of initial public offering issuance costs								(578,000)		(1,160,000)		(2,928,000)		(5,521,000)	(1,092,000)
Net cash provided by (used in) financing activities				(1,490,000)				(9,069,000)	(109,273,000)	(21,828,000)	(141,341,000)	261,839,000		253,119,000	61,806,000
Net increase (decrease) in cash, cash equivalents, and restricted cash				89,449,000				(37,020,000)	90,581,000	(30,740,000)	77,390,000	263,614,000		99,873,000	(37,303,000)
Beginning of period	357,875,000	371,066,000	369,934,000	280,485,000	444,226,000	149,872,000	143,592,000	180,612,000	280,485,000	180,612,000	280,485,000	180,612,000	280,485,000	180,612,000	217,915,000
End of period		357,875,000	371,066,000	369,934,000	280,485,000	444,226,000	149,872,000	143,592,000	371,066,000	149,872,000	357,875,000	444,226,000		280,485,000	180,612,000
Supplemental disclosure of cash flow information:
Cash paid during the period for interest				14,545,000				11,216,000	23,867,000	16,540,000	35,894,000	30,601,000		39,465,000	21,948,000
Cash paid during the period for taxes				222,000				401,000	497,000	625,000	715,000	1,052,000		1,748,000	616,000
Restatement Adjustment
Cash flows from operating activities:
Net income (loss)		(5,802,000)	(9,935,000)	(21,056,000)	(15,668,000)	(1,922,000)	(10,322,000)	(3,875,000)	(30,991,000)	(14,197,000)	(36,793,000)	(16,119,000)		(31,787,000)	(13,763,000)
Depreciation and amortization				2,954,000				2,457,000	6,011,000	4,912,000	9,132,000	7,616,000		10,428,000	8,271,000
Write-off of property, plant and equipment, net				0					0	0	0	0		0	0
Write-off of PPA II and PPA IIIb decommissioned assets									0		0
Revaluation of derivative contracts				540,000				0	1,081,000	0	1,620,000	755,000		550,000	288,000
Stock-based compensation				3,940,000				191,000	4,086,000	(292,000)	5,278,000	(10,777,000)		(11,802,000)	(1,378,000)
Loss (gain) on long-term REC purchase contract				0				0	0	0	0	0		0	0
Revaluation of stock warrants								0		0		0		0	0
Debt make-whole expense									0		0
Amortization of debt issuance cost				0				0	0	0	0	0		0	0
Accounts receivable				(98,000)				(32,000)	(274,000)	(195,000)	(318,000)	(332,000)		(453,000)	(1,607,000)
Inventories				(4,845,000)				3,291,000	(5,345,000)	7,915,000	6,121,000	4,037,000		5,242,000	(3,531,000)
Deferred cost of revenue				(37,098,000)				(3,541,000)	(57,991,000)	(28,362,000)	(59,198,000)	(34,343,000)		(74,101,000)	39,701,000
Customer financing receivable and other				0				0	0	0	0	0		0	0
Prepaid expenses and other current assets				1,423,000				929,000	1,752,000	220,000	176,000	(1,585,000)		(968,000)	1,193,000
Other long-term assets				(396,000)				(418,000)	(1,029,000)	(866,000)	(1,229,000)	(1,398,000)		(2,099,000)	(3,869,000)
Accounts payable				0				0	0	0	0	0		0	0
Accrued warranty				50,000				10,000	114,000	(300,000)	109,000	(324,000)		(928,000)	(320,000)
Accrued expenses and other current liabilities				(1,196,000)				(515,000)	(1,632,000)	(1,386,000)	162,000	626,000		816,000	(602,000)
Deferred revenue and customer deposits				49,428,000				6,620,000	71,325,000	9,787,000	74,765,000	17,431,000		70,222,000	(43,571,000)
Other long-term liabilities				679,000				981,000	1,303,000	497,000	2,477,000	1,362,000		1,349,000	(5,602,000)
Net cash provided by (used in) operating activities				(5,675,000)				6,098,000	(11,590,000)	(22,267,000)	2,302,000	(33,051,000)		(33,531,000)	(24,790,000)
Cash flows from investing activities:
Purchase of property, plant and equipment				(3,403,000)				(4,635,000)	(4,737,000)	(11,550,000)	(16,216,000)	(20,283,000)		(30,546,000)	(56,314,000)
Payments for acquisition of intangible assets				0					0		0	0		0
Purchase of marketable securities								0		0		0		0	0
Proceeds from maturity of marketable securities				0				0	0	0	0	0		0	0
Net cash provided by (used in) investing activities				(3,403,000)				(4,635,000)	(4,737,000)	(11,550,000)	(16,216,000)	(20,283,000)		(30,546,000)	(56,314,000)
Cash flows from financing activities:
Borrowings from issuance of debt															0
Repayment of debt				0				0	0	0	0	0		0	0
Repayment of debt to related parties				0				0	0	0	0	0		0	0
Debt make-whole payment									0		0
Debt issuance costs															0
Proceeds from financing obligations				10,961,000					20,333,000	36,799,000	20,333,000	57,897,000		70,265,000	84,314,000
Repayment of financing obligations				(1,883,000)				1,463,000	(4,006,000)	2,982,000	(6,419,000)	(4,563,000)		(6,188,000)	(3,210,000)
Proceeds from noncontrolling and redeemable noncontrolling interests															0
Payments to noncontrolling and redeemable noncontrolling interests									0		0
Distributions to noncontrolling and redeemable noncontrolling interests				0				0	0	0	0	0		0	0
Proceeds from issuance of common stock				0				0	0	0	0	0		0	0
Proceeds from public offerings, net of underwriting discounts and commissions												0		0
Payments of initial public offering issuance costs								0		0		0		0	0
Net cash provided by (used in) financing activities				9,078,000				(1,463,000)	16,327,000	33,817,000	13,914,000	53,334,000		64,077,000	81,104,000
Net increase (decrease) in cash, cash equivalents, and restricted cash				0				0	0	0	0	0		0	0
Beginning of period	$ 0	0	0	0	0	0	0	0	0	0	0	0	$ 0	0	0
End of period		$ 0	$ 0	0	$ 0	$ 0	$ 0	0	0	0	0	0		0	0
Supplemental disclosure of cash flow information:
Cash paid during the period for interest				5,838,000				4,613,000	11,835,000	9,233,000	17,878,000	14,505,000		20,084,000	15,680,000
Cash paid during the period for taxes				0				0	0	0	0	0		0	0
Valuation Adjustment | Restatement Adjustment
Cash flows from operating activities:
Revaluation of derivative contracts														755,000
Capitalized Stock-Based Compensation | Restatement Adjustment
Cash flows from operating activities:
Stock-based compensation				4,400,000				(602,000)	4,672,000	(1,026,000)	5,864,000	(10,068,000)		(10,256,000)	(634,000)
Deferred cost of revenue				94,000				(348,000)	(1,506,000)	(250,000)	1,432,000	(2,969,000)		(2,216,000)	609,000
Capitalized Stock-Based Compensation, Managed Services Program | Restatement Adjustment
Cash flows from operating activities:
Stock-based compensation				(460,000)				793,000	(586,000)	733,000	(586,000)	(709,000)		(1,546,000)	(744,000)
Reclassification Of Lease Arrangements | Restatement Adjustment
Cash flows from operating activities:
Deferred cost of revenue				(37,192,000)				$ (3,193,000)	(56,485,000)	$ (28,112,000)	(60,630,000)	$ (31,373,000)		(71,884,000)	39,091,000
Timing Difference | Restatement Adjustment
Cash flows from operating activities:
Other long-term assets														100,000	1,700,000
Reclassification Of Payments | Restatement Adjustment
Cash flows from operating activities:
Other long-term assets														1,900,000	1,800,000
Commission Payments | Restatement Adjustment
Cash flows from operating activities:
Other long-term assets														100,000	400,000
Grid Pricing Escalation | Restatement Adjustment
Cash flows from operating activities:
Revaluation of derivative contracts														200,000
Accrued warranty				$ 143,000					$ 312,000		$ 432,000			$ 300,000
Accrued expenses and other current liabilities															$ (261,000)