QUARTERLY FINANCIAL DATA (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information

The following tables sets forth the unaudited consolidated statements of operations for each of the fiscal quarters in 2020 and 2019.

	Fiscal Quarter Ended
	December 31, 2020		September 30, 2020		June 30, 2020		March 31, 2020		December 31, 2019		September 30, 2019		June 30, 2019		March 31, 2019
Solar revenues	—		—		36		58		49		296		13		124
Cost of solar revenues	—		—		30		43		44		141		24		62
Gross profit	—		—		6		15		5		155		(11)		62
Operating Expenses:
Research and development	67,521		51,496		42,525		24,077		22,781		9,482		11,854		23,397
Selling, general and administrative	64,903		65,782		44,104		7,935		5,154		3,693		5,344		6,501
Impairment expense	14,415		—		—		—		—		—		—		—
Total operating expenses	146,839		117,278		86,629		32,012		27,935		13,175		17,198		29,898
Loss from operations	(146,839)		(117,278)		(86,623)		(31,997)		(27,930)		(13,020)		(17,209)		(29,836)
Other income (expense):
Interest income (expense), net	(53)		171		22		62		374		411		338		333
Revaluation of Series A redeemable convertible preferred stock warrant liability	—		—		—		—		—		(2,844)		98		(593)
Loss forward contract liability	—		—		—		(1,324)		—		—		—		—
Other income (expense), net	(597)		(340)		(23)		114		1,278		85		9		1
Loss before income taxes and equity in net loss of affiliate	(147,489)		(117,447)		(86,624)		(33,145)		(26,278)		(15,368)		(16,764)		(30,095)
Income tax expense (benefit)	(1,030)		2		1		1		1		146		2		2
Loss before equity in net loss of affiliate	(146,459)		(117,449)		(86,625)		(33,146)		(26,279)		(15,514)		(16,766)		(30,097)
Equity in net loss of affiliate	(637)		—		—		—		—		—		—		—
Net loss	(147,096)		(117,449)		(86,625)		(33,146)		(26,279)		(15,514)		(16,766)		(30,097)
Premium paid on repurchase of redeemable convertible preferred stock	—		—		(13,407)		—		(16,816)		—		—		—
Net loss attributable to common stockholders, basic and diluted	(147,096)		(117,449)		(100,032)		(33,146)		(43,095)		(15,514)		(16,766)		(30,097)
Net loss per share attributable to common stockholders, basic and diluted	$	(0.38)	$	(0.31)	$	(0.33)	$	(0.12)	$	(0.16)	$	(0.06)	$	(0.06)	$	(0.12)
Weighted-average shares used to compute net loss per share attributable to common stockholders, basic and diluted	385,983,645		377,660,477		303,785,616		271,896,258		268,698,455		260,534,724		260,406,343		260,406,343