Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect of Accounting Change [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Cumulative Effect of Accounting Change [Member]	Accumulated Other Comprehensive Gain (Loss) [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Cumulative Effect of Accounting Change [Member]
BALANCE at Dec. 31, 2019	$ 818,187		$ 8	$ 3,112,130		$ 50	$ (2,294,001)
BALANCE (in shares) at Dec. 31, 2019			75,185,000
Exercise of options for common stock	76,492			76,492
Exercise of options for common stock, shares			1,443,000
Vest of restricted stock units/awards			159,000
Shares withheld for taxes	(6,333)			(6,333)
Shares withheld for taxes, shares			(37,000)
Issuance of common stock for cash, net of offering costs	312,053			312,053
Issuance of common stock for cash, net of offering costs, shares			2,522,000
Issuance of common stock under employee stock purchase plan	7,465			7,465
Issuance of common stock under employee stock purchase plan, shares			102,000
Stock-based compensation	108,070			108,070
Purchase Of Capped Call Share Options For 2027 Notes	0
Partial settlement of capped call share options for 2024 Notes	0
Unrealized losses from available-for-sale securities, net of tax	(47)					(47)
Net loss	(554,128)						(554,128)
BALANCE at Dec. 31, 2020	761,759		$ 8	3,609,877		3	(2,848,129)
BALANCE (in shares) at Dec. 31, 2020			79,374,000
Exercise of options for common stock	12,963			12,963
Exercise of options for common stock, shares			283,000
Vest of restricted stock units/awards			277,000
Shares withheld for taxes	(1,432)			(1,432)
Shares withheld for taxes, shares			(18,000)
Issuance of common stock for cash, net of offering costs	548,532		$ 1	548,531
Issuance of common stock for cash, net of offering costs, shares			7,099,000
Issuance of common stock under employee stock purchase plan	7,839			7,839
Issuance of common stock under employee stock purchase plan, shares			112,000
Stock-based compensation	113,943			113,943
Purchase Of Capped Call Share Options For 2027 Notes	0
Partial settlement of capped call share options for 2024 Notes	0
Unrealized losses from available-for-sale securities, net of tax	(23)					(23)
Net loss	(418,780)						(418,780)
BALANCE at Dec. 31, 2021	928,009	$ (96,792)	$ 9	4,134,768	$ (156,953)	(20)	(3,206,748)	$ 60,161
BALANCE (in shares) at Dec. 31, 2021			87,127,000
Exercise of options for common stock	$ 22,573			22,573
Exercise of options for common stock, shares	318,258		318,000
Vest of restricted stock units/awards			389,000
Issuance of common stock under employee stock purchase plan	$ 7,470			7,470
Issuance of common stock under employee stock purchase plan, shares			116,000
Stock-based compensation	233,018			233,018
Purchase Of Capped Call Share Options For 2027 Notes	(127,305)			(127,305)
Partial settlement of capped call share options for 2024 Notes	26,317			26,317
Unrealized losses from available-for-sale securities, net of tax	(1,644)					(1,644)
Net loss	(703,488)						(703,488)
BALANCE at Dec. 31, 2022	$ 384,950		$ 9	$ 4,296,841		$ (1,664)	$ (3,910,236)
BALANCE (in shares) at Dec. 31, 2022			87,950,000