Quarterly Financial Information (Unaudited) - Statements of Operations and Comprehensive Loss (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022
Revenue:
Revenue											$ 29,065	$ 2,739
Other revenue											432	858
Total revenues											29,497	3,597
Operating expenses:
Selling, general and administrative											165,510	140,326
Research and development											167,652	200,439
Cost of product revenue											33,527	10,077
Gross margin											(4,030)	(6,480)
Restructuring expense											0	4,940
Total operating expenses											333,162	345,705
Loss on fixed assets disposal											92,930	102,000
Loss from operations											(244,262)	(250,185)
Interest income											9,869	1,032
Interest expense											(16,353)	(6,322)
Other income, net											38,707	25,250
Loss before income taxes											(212,039)	(230,225)
Income tax benefit (expense)											126	(117)
Net loss											$ (211,913)	$ (230,342)
Net income (loss) per share - basic (in dollars per share)											$ (1.93)	$ (2.93)
Net income (loss) per share - diluted (in dollars per share)											$ (1.93)	$ (2.93)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)											109,825	78,585
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)											109,825	78,585
Other comprehensive income (loss):
Other comprehensive income (loss)											$ 2,274	$ (1,159)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent											(209,639)	(231,501)
Other comprehensive income (loss), tax	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	0
Previously Reported
Revenue:
Revenue	12,281	6,837	2,296	0	1,331	1,408	9,133	2,739	21,414	2,739		2,739
Other revenue	111	53	85	71	188	537	138	725	249	795		858
Total revenues	12,392	6,890	2,381	71	1,519	1,945	9,271	3,464	21,663	3,534		3,597
Operating expenses:
Selling, general and administrative	40,703	40,349	37,354	33,402	36,694	36,106	77,703	72,800	118,406	106,201		136,908
Research and development	45,463	42,274	46,144	53,149	63,841	77,875	88,418	141,716	133,881	194,864		240,764
Cost of product revenue	10,955	9,564	3,376	0	1,745	8,310	12,940	10,055	23,895	10,056		10,077
Gross margin	1,437	(2,674)	(995)	71	(226)	(6,365)	(3,669)	(6,591)	(2,232)	(6,522)		(6,480)
Restructuring expense				(1,699)	6,639			6,639		4,940		4,940
Total operating expenses	86,166	82,623	83,498	84,852	107,174	113,981	166,121	221,155	252,287	306,005		382,612
Loss on fixed assets disposal			92,930				92,930		92,930			102,000
Loss from operations	(84,729)	(85,297)	8,437	(84,781)	(107,400)	(120,346)	(76,860)	(227,746)	(161,589)	(312,527)		(287,092)
Interest income	2,454	2,679	2,828	383	174	106	5,507	280	7,961	663		1,032
Interest expense	0	0	(3)	0	0	0	(3)	0	(3)	0		0
Other income, net	10,544	9,630	9,978	7,885	7,088	(1,912)	19,608	5,176	30,152	13,061		19,599
Loss before income taxes	(71,731)	(72,988)	21,240	(76,513)	(100,138)	(122,152)	(51,748)	(222,290)	(123,479)	(298,803)		(266,461)
Income tax benefit (expense)	0	80	0	(7)	0	0	80	0	80	(7)		(117)
Net loss	$ (71,731)	$ (72,908)	$ 21,240	$ (76,520)	$ (100,138)	$ (122,152)	$ (51,668)	$ (222,290)	$ (123,399)	$ (298,810)		$ (266,578)
Net income (loss) per share - basic (in dollars per share)	$ (0.66)	$ (0.67)	$ 0.21	$ (0.94)	$ (1.36)	$ (1.66)	$ (0.49)	$ (3.02)	$ (1.15)	$ (3.91)		$ (3.39)
Net income (loss) per share - diluted (in dollars per share)	$ (0.66)	$ (0.67)	$ 0.21	$ (0.94)	$ (1.36)	$ (1.66)	$ (0.49)	$ (3.02)	$ (1.15)	$ (3.91)		$ (3.39)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	109,098	108,685	102,920	81,543	73,767	73,688	105,819	73,727	106,924	76,361		78,585
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	109,098	108,685	103,303	81,543	73,767	73,688	105,819	73,727	106,924	76,361		78,585
Other comprehensive income (loss):
Other comprehensive income (loss)	$ 137	$ 722	$ 984	$ (214)	$ 43	$ (1,548)	$ 1,706	$ (1,505)	$ 1,843	$ (1,719)		$ (1,159)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(71,594)	(72,186)	22,224	(76,734)	(100,095)	(123,700)	(49,962)	(223,795)	(121,556)	(300,529)		(267,737)
Revision of Prior Period, Error Correction, Adjustment | Adjustments to Leases
Revenue:
Revenue	0	0	0	0	0	0	0	0	0	0		0
Other revenue	0	0	0	0	0	0	0	0	0	0		0
Total revenues	0	0	0	0	0	0	0	0	0	0		0
Operating expenses:
Selling, general and administrative	68	113	113	273	(314)	(147)	226	(461)	294	(188)		3,516
Research and development	14,757	(10,189)	(4,516)	(2,923)	(12,355)	(15,511)	(14,705)	(27,866)	52	(30,789)		(40,121)
Cost of product revenue	(1,829)	(2,867)	2,136	0	0	0	(731)	0	(2,560)	0		0
Gross margin	1,829	2,867	(2,136)	0	0	0	731	0	2,560	0		0
Restructuring expense				0	0			0		0		0
Total operating expenses	14,825	(10,076)	(4,403)	(2,650)	(12,669)	(15,658)	(14,479)	(28,327)	346	(30,977)		(36,605)
Loss on fixed assets disposal			0				0		0			0
Loss from operations	(12,996)	12,943	2,267	2,650	12,669	15,658	15,210	28,327	2,214	30,977		36,605
Interest income	0	0	0	0	0	0	0	0	0	0		0
Interest expense	(4,311)	(3,750)	(4,267)	(1,552)	(922)	(1,028)	(8,017)	(1,950)	(12,328)	(3,502)		(6,322)
Other income, net	168	289	(351)	3,156	1,512	530	(62)	2,042	106	5,198		5,651
Loss before income taxes	(17,139)	9,482	(2,351)	4,254	13,259	15,160	7,131	28,419	(10,008)	32,673		35,934
Income tax benefit (expense)	0	0	0	0	0	0		0	0	0		0
Net loss	$ (17,139)	$ 9,482	$ (2,351)	$ 4,254	$ 13,259	$ 15,160	$ 7,131	$ 28,419	$ (10,008)	$ 32,673		$ 35,934
Net income (loss) per share - basic (in dollars per share)	$ (0.16)	$ 0.09	$ (0.02)	$ 0.05	$ 0.18	$ 0.21	$ 0.07	$ 0.39	$ (0.09)	$ 0.43		$ 0.46
Net income (loss) per share - diluted (in dollars per share)	$ (0.16)	$ 0.09	$ (0.02)	$ 0.05	$ 0.18	$ 0.21	$ 0.07	$ 0.39	$ (0.09)	$ 0.43		$ 0.46
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	0	0	0	0	0	0	0	0	0	0		0
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	0	0	0	0	0	0	0	0	0	0		0
Other comprehensive income (loss):
Other comprehensive income (loss)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(17,139)	9,482	(2,351)	4,254	13,259	15,160	7,131	28,419	(10,008)	32,673		35,934
Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Revenue:
Revenue	0	0	0	0	0	0	0	0	0	0		0
Other revenue	0	0	0	0	0	0	0	0	0	0		0
Total revenues	0	0	0	0	0	0	0	0	0	0		0
Operating expenses:
Selling, general and administrative	0	0	0	4	(261)	(510)	0	(771)	0	(767)		(98)
Research and development	(1,719)	(637)	(41)	(5,214)	(262)	(930)	(678)	(1,192)	(2,397)	(6,406)		(204)
Cost of product revenue	0	0	0	0	0	0	0	0	0	0		0
Gross margin	0	0	0	0	0	0	0	0	0	0		0
Restructuring expense				0	0			0		0		0
Total operating expenses	(1,719)	(637)	(41)	(5,210)	(523)	(1,440)	(678)	(1,963)	(2,397)	(7,173)		(302)
Loss on fixed assets disposal			0				0		0			0
Loss from operations	1,719	637	41	5,210	523	1,440	678	1,963	2,397	7,173		302
Interest income	0	0	0	0	0	0	0	0	0	0		0
Interest expense	0	0	0	0	0	0	0	0	0	0		0
Other income, net	(81)	0	0	0	0	0	0	0	(81)	0		0
Loss before income taxes	1,638	637	41	5,210	523	1,440	678	1,963	2,316	7,173		302
Income tax benefit (expense)	0	0	0	0	0	0	0	0	0	0		0
Net loss	$ 1,638	$ 637	$ 41	$ 5,210	$ 523	$ 1,440	$ 678	$ 1,963	$ 2,316	$ 7,173		$ 302
Net income (loss) per share - basic (in dollars per share)	$ 0.02	$ 0.01	$ 0	$ 0.06	$ 0.01	$ 0.02	$ 0.01	$ 0.03	$ 0.02	$ 0.09		$ 0
Net income (loss) per share - diluted (in dollars per share)	$ 0.02	$ 0.01	$ 0	$ 0.06	$ 0.01	$ 0.02	$ 0.01	$ 0.03	$ 0.02	$ 0.09		$ 0
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	0	0	0	0	0	0	0	0	0	0		0
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	0	0	0	0	0	0	0	0	0	0		0
Other comprehensive income (loss):
Other comprehensive income (loss)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	1,638	637	41	5,210	523	1,440	678	1,963	2,316	7,173		$ 302
As Restated
Revenue:
Revenue	12,281	6,837	2,296	0	1,331	1,408	9,133	2,739	21,414	2,739
Other revenue	111	53	85	71	188	537	138	725	249	795
Total revenues	12,392	6,890	2,381	71	1,519	1,945	9,271	3,464	21,663	3,534
Operating expenses:
Selling, general and administrative	40,771	40,462	37,467	33,679	36,119	35,449	77,929	71,568	118,700	105,246
Research and development	58,501	31,448	41,587	45,012	51,224	61,434	73,035	112,658	131,536	157,669
Cost of product revenue	9,126	6,697	5,512	0	1,745	8,310	12,209	10,055	21,335	10,056
Gross margin	3,266	193	(3,131)	71	(226)	(6,365)	(2,938)	(6,591)	328	(6,522)
Restructuring expense				(1,699)	6,639			6,639		4,940
Total operating expenses	99,272	71,910	79,054	76,992	93,982	96,883	150,964	190,865	250,236	267,855
Loss on fixed assets disposal			92,930				92,930		92,930
Loss from operations	(96,006)	(71,717)	10,745	(76,921)	(94,208)	(103,248)	(60,972)	(197,456)	(156,978)	(274,377)
Interest income	2,454	2,679	2,828	383	174	106	5,507	280	7,961	663
Interest expense	(4,311)	(3,750)	(4,270)	(1,552)	(922)	(1,028)	(8,020)	(1,950)	(12,331)	(3,502)
Other income, net	10,631	9,919	9,627	11,041	8,600	(1,382)	19,546	7,218	30,177	18,259
Loss before income taxes	(87,232)	(62,869)	18,930	(67,049)	(86,356)	(105,552)	(43,939)	(191,908)	(131,171)	(258,957)
Income tax benefit (expense)	0	80	0	(7)	0	0	80	0	80	(7)
Net loss	$ (87,232)	$ (62,789)	$ 18,930	$ (67,056)	$ (86,356)	$ (105,552)	$ (43,859)	$ (191,908)	$ (131,091)	$ (258,964)
Net income (loss) per share - basic (in dollars per share)	$ (0.80)	$ (0.58)	$ 0.18	$ (0.82)	$ (1.17)	$ (1.43)	$ (0.41)	$ (2.60)	$ (1.23)	$ (3.39)
Net income (loss) per share - diluted (in dollars per share)	$ (0.80)	$ (0.58)	$ 0.18	$ (0.82)	$ (1.17)	$ (1.43)	$ (0.41)	$ (2.60)	$ (1.23)	$ (3.39)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	109,098	108,685	102,920	81,543	73,767	73,688	105,819	73,727	106,924	76,361
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	109,098	108,685	103,303	81,543	73,767	73,688	105,819	73,727	106,924	76,361
Other comprehensive income (loss):
Other comprehensive income (loss)	$ 137	$ 722	$ 984	$ (214)	$ 43	$ (1,548)	$ 1,706	$ (1,505)	$ 1,843	$ (1,719)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ (87,095)	$ (62,067)	$ 19,914	$ (67,270)	$ (86,313)	$ (107,100)	$ (42,153)	$ (193,413)	$ (129,248)	$ (260,683)