CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Total	Ordinary Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Noncontrolling Interests
Balance at the beginning of period at Dec. 31, 2018	$ 1,753,647	$ 1,739,202	$ 77	$ 2,744,814	$ 1,526	$ (1,007,215)	$ 14,445
Balance at the beginning of period (in shares) at Dec. 31, 2018			776,263,184
Increase (Decrease) in Stockholders' Equity
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			916,383
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	6,269	6,269	$ 1	6,268
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			2,066,383
Share-based compensation	26,392	26,392		26,392
Other comprehensive income (loss)	4,440	4,546			4,546		(106)
Net loss	(168,069)	(167,640)				(167,640)	(429)
Balance at the ending of period (in shares) at Mar. 31, 2019			777,413,184
Balance at the end of period at Mar. 31, 2019	1,622,679	1,608,769	$ 78	2,777,474	6,072	(1,174,855)	13,910
Balance at the beginning of period at Dec. 31, 2018	1,753,647	1,739,202	$ 77	2,744,814	1,526	(1,007,215)	14,445
Balance at the beginning of period (in shares) at Dec. 31, 2018			776,263,184
Increase (Decrease) in Stockholders' Equity
Net loss	(562,683)
Balance at the ending of period (in shares) at Sep. 30, 2019			784,440,698
Balance at the end of period at Sep. 30, 2019	1,294,237	1,278,478	$ 78	2,861,012	(14,830)	(1,567,782)	15,759
Balance at the beginning of period at Mar. 31, 2019	1,622,679	1,608,769	$ 78	2,777,474	6,072	(1,174,855)	13,910
Balance at the beginning of period (in shares) at Mar. 31, 2019			777,413,184
Increase (Decrease) in Stockholders' Equity
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			3,223,701
Contributions from shareholders	4,000						4,000
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	4,373	4,373		4,373
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			3,802,747
Share-based compensation	32,602	32,602		32,602
Other comprehensive income (loss)	(6,436)	(6,297)			(6,297)		(139)
Net loss	(85,954)	(85,570)				(85,570)	(384)
Balance at the ending of period (in shares) at Jun. 30, 2019			784,439,632
Balance at the end of period at Jun. 30, 2019	1,571,264	1,553,877	$ 78	2,814,449	(225)	(1,260,425)	17,387
Increase (Decrease) in Stockholders' Equity
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			(4,170,283)
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	9,745	9,745		9,745
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			4,171,349
Share-based compensation	36,818	36,818		36,818
Other comprehensive income (loss)	(14,930)	(14,605)			(14,605)		(325)
Net loss	(308,660)	(307,357)				(307,357)	(1,303)
Balance at the ending of period (in shares) at Sep. 30, 2019			784,440,698
Balance at the end of period at Sep. 30, 2019	1,294,237	1,278,478	$ 78	2,861,012	(14,830)	(1,567,782)	15,759
Balance at the beginning of period at Dec. 31, 2019	$ 978,355	962,205	$ 79	2,925,970	(8,001)	(1,955,843)	16,150
Balance at the beginning of period (in shares) at Dec. 31, 2019	801,340,698		801,340,698
Increase (Decrease) in Stockholders' Equity
Issuance of ordinary shares in connection with collaboration	$ 2,162,407	2,162,407	$ 21	2,162,386
Issuance of ordinary shares in connection with collaboration (in shares)			206,635,013
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			3,705,468
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	11,629	11,629	$ 1	11,628
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			3,706,573
Share-based compensation	38,255	38,255		38,255
Other comprehensive income (loss)	1,349	1,453			1,453		(104)
Net loss	(364,939)	(363,735)				(363,735)	(1,204)
Balance at the ending of period (in shares) at Mar. 31, 2020			1,007,976,816
Balance at the end of period at Mar. 31, 2020	2,827,056	2,812,214	$ 101	5,138,239	(6,548)	(2,319,578)	14,842
Balance at the beginning of period at Dec. 31, 2019	$ 978,355	962,205	$ 79	2,925,970	(8,001)	(1,955,843)	16,150
Balance at the beginning of period (in shares) at Dec. 31, 2019	801,340,698		801,340,698
Increase (Decrease) in Stockholders' Equity
Other comprehensive income (loss)					7,582
Net loss	$ (1,127,874)
Balance at the ending of period (in shares) at Sep. 30, 2020	1,182,916,659		1,182,916,659
Balance at the end of period at Sep. 30, 2020	$ 4,296,514	4,287,494	$ 118	7,367,799	(419)	(3,080,004)	9,020
Balance at the beginning of period at Mar. 31, 2020	2,827,056	2,812,214	$ 101	5,138,239	(6,548)	(2,319,578)	14,842
Balance at the beginning of period (in shares) at Mar. 31, 2020			1,007,976,816
Increase (Decrease) in Stockholders' Equity
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			3,493,516
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	16,569	16,569	$ 1	16,568
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			10,493,392
Share-based compensation	45,468	45,468		45,468
Deconsolidation of a subsidiary	(3,545)						(3,545)
Other comprehensive income (loss)	(2,738)	(2,751)			(2,751)		13
Net loss	(336,318)	(335,202)				(335,202)	(1,116)
Balance at the ending of period (in shares) at Jun. 30, 2020			1,014,976,692
Balance at the end of period at Jun. 30, 2020	2,546,492	2,536,298	$ 102	5,200,275	(9,299)	(2,654,780)	10,194
Increase (Decrease) in Stockholders' Equity
Issuance of ordinary shares in connection with collaboration	2,069,610	2,069,610	$ 14	2,069,596
Issuance of ordinary shares in connection with collaboration (in shares)			145,838,979
Issuance of shares reserved for share option exercises	1	1	$ 1
Issuance (use) of shares reserved for share option exercises and RSU releases (in shares)			5,525,182
Exercise of options, ESPP and release of Restricted Share Units (RSUs)	47,632	47,632	$ 1	47,631
Exercise of options, ESPP and release of Restricted Share Units (RSUs) (in shares)			16,575,806
Share-based compensation	50,297	50,297		50,297
Other comprehensive income (loss)	9,099	8,880			8,880		219
Net loss	$ (426,617)	(425,224)				(425,224)	(1,393)
Balance at the ending of period (in shares) at Sep. 30, 2020	1,182,916,659		1,182,916,659
Balance at the end of period at Sep. 30, 2020	$ 4,296,514	$ 4,287,494	$ 118	$ 7,367,799	$ (419)	$ (3,080,004)	$ 9,020