CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2020	$ 1,027		$ 3,210	$ 1	$ (2,184)
Beginning balance, Shares at Dec. 31, 2020		587
Issuance of common stock upon exercise of options for cash	3		3
Issuance of common stock upon exercise of options for cash, Shares		5
Issuance of common stock upon settlement of restricted stock units	(5)		(5)
Issuance of common stock upon settlement of restricted stock units, Shares		33
Net exercises of common stock warrant, Shares		1
Issuance of common stock through ESPP	3		3
Issuance of common stock through ESPP, Shares		1
Stock-based compensation	74		74
Other comprehensive gain (loss), net	(1)			(1)
Net loss	(239)				(239)
Ending balance at Jun. 30, 2021	862		3,285		(2,423)
Ending balance, Shares at Jun. 30, 2021		627
Beginning balance at Mar. 31, 2021	930		3,243	(1)	(2,312)
Beginning balance, Shares at Mar. 31, 2021		618
Issuance of common stock upon exercise of options for cash	2		2
Issuance of common stock upon exercise of options for cash, Shares		3
Issuance of common stock upon settlement of restricted stock units, Shares		4
Net exercises of common stock warrant, Shares		1
Issuance of common stock through ESPP	3		3
Issuance of common stock through ESPP, Shares		1
Stock-based compensation	37		37
Other comprehensive gain (loss), net	1			1
Net loss	(111)				(111)
Ending balance at Jun. 30, 2021	862		3,285		(2,423)
Ending balance, Shares at Jun. 30, 2021		627
Beginning balance at Dec. 31, 2021	$ 818		3,360	3	(2,545)
Beginning balance, Shares at Dec. 31, 2021	658	658
Issuance of common stock upon exercise of options for cash, Shares	1	1
Issuance of common stock upon settlement of restricted stock units, Shares		13
Shares withheld related to net share settlement	$ (5)		(5)
Shares withheld related to net share settlement, Shares		(3)
Issuance of common stock through ESPP	1		1
Issuance of common stock through ESPP, Shares		1
Stock-based compensation	27		27
Other comprehensive gain (loss), net	(9)			(9)
Net loss	(150)				(150)
Ending balance at Jun. 30, 2022	$ 682		3,383	(6)	(2,695)
Ending balance, Shares at Jun. 30, 2022	670	670
Beginning balance at Mar. 31, 2022	$ 755		3,358	2	(2,605)
Beginning balance, Shares at Mar. 31, 2022		664
Issuance of common stock upon settlement of restricted stock units, Shares		8
Shares withheld related to net share settlement	(5)		(5)
Shares withheld related to net share settlement, Shares		(3)
Issuance of common stock through ESPP	1		1
Issuance of common stock through ESPP, Shares		1
Stock-based compensation	29		29
Other comprehensive gain (loss), net	(8)			(8)
Net loss	(90)				(90)
Ending balance at Jun. 30, 2022	$ 682		$ 3,383	$ (6)	$ (2,695)
Ending balance, Shares at Jun. 30, 2022	670	670