Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating activities:
Net loss	$ (59,544)	$ (69,580)	$ (59,959)	$ (60,747)	$ (212,162)	$ (296,457)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization					1,485	1,559
Amortization of intangibles	9,000		6,100		27,032	24,307
Intangible asset impairment charge					0	115,527
Amortization of premium/discount on investments					(15)	(31)
Non-cash interest expense related to sale of future royalties					6,779	0
Non-cash royalty revenue related to sale of future royalties					(425)	0
Non-cash interest expense					852	1,255
Non-cash operating lease expense					(1,415)	(1,660)
Fair value step-up of inventory sold or written off					21,575	39,522
Write-down of inventory	1,700		8,500		7,126	18,608
Change in excess inventory purchase commitments	(6,000)				15,376	10,304
Stock-based compensation					18,099	18,372
Change in fair value of derivative liability	0	80			(490)	340
Changes in operating assets and liabilities:
Accounts receivable					(22,837)	14,398
Inventory					(35,282)	6,415
Prepaid expenses and other current assets					(25,020)	(2,279)
Other long-term assets					4,728	(6,518)
Accounts payable					(14,933)	3,028
Accrued expense					15,099	(6,072)
Operating lease liabilities					1,173	1,032
Deferred revenue					3,098	(21,256)
Net cash used in operating activities					(190,157)	(79,606)
Investing activities:
Purchase of equipment					(59)	0
Purchase of available for sale securities					0	(99,932)
Proceeds from the maturities of available for sale securities					40,000	245
Net cash provided by (used in) investing activities					39,941	(99,687)
Financing activities:
Proceeds from sale of future royalties, net					44,783	0
Proceeds from the issuance of common stock, net of issuance costs					82,799	198,883
Proceeds from the sale of stock under employee stock purchase plan					746	1,100
Proceeds from the exercise of stock options					0	1,226
Net cash provided by financing activities					128,328	201,209
Increase (decrease) in cash, cash equivalents, and restricted cash					(21,888)	21,916
Cash, cash equivalents, and restricted cash at beginning of the period		$ 231,132		$ 149,804	231,132	149,804	$ 149,804
Cash, cash equivalents, and restricted cash at end of the period	$ 209,244		$ 171,720		209,244	171,720	$ 231,132
Non-cash financing activities
Unpaid offering costs					$ 57	$ 75