Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (269,108)	$ (143,551)	$ (97,165)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	612	547	319
Amortization (accretion) of premiums and discounts on investments	12	(97)	(200)
Amortization of discount and issuance costs on convertible notes	1,621	1,741	0
Acquired in-process research and development	0	12,500	0
Gain on extinguishment of convertible debt	(2,646)	0	0
Non-cash interest expense related to the revenue interest liability	33,907	19,560	8,120
Stock-based compensation expense	24,306	28,385	25,884
Changes in assets and liabilities:
Accounts receivable	(10,546)	(12,388)	0
Prepaids and other assets	99	(2,405)	(3,396)
Deferred revenue	4,655	(490)	2,152
Inventories	(18,258)	(16,136)	0
Accounts payable	(34,099)	23,106	(16,055)
Other accrued liabilities	6,926	2,761	10,000
Other long-term liabilities	(1,290)	1,290	0
Net cash used in operating activities	(263,809)	(85,177)	(70,341)
Investing activities
Purchases of investments	(50,484)	(4,420)	(34,326)
Proceeds from sales/maturities of investments	0	39,145	99,510
Purchases of in-process research and development	0	(12,500)	0
Purchase of property and equipment	0	(869)	(953)
Net cash (used in) provided by investing activities	(50,484)	21,356	64,231
Financing activities
Proceeds from revenue interest liability, net of issuance costs	49,917	25,000	124,424
Proceeds from issuance of common stock and warrants from offering, net of issuance costs	208,975	0	0
Proceeds from issuance of common stock from ATM Program, net of issuance costs	9,713	0	0
Proceeds from exercise of common stock options	3,762	6,634	11,771
Proceeds from issuance of convertible notes	0	280,000	0
Prepayment of forward stock repurchase transaction	0	(55,000)	0
Payment for debt issuance costs on convertible notes	(440)	(8,405)	0
Purchase of capped call options associated with convertible notes	0	(46,004)	0
Payments on revenue interest liability	(3,389)	(500)	0
Payment for debt issuance costs, debt-to-equity conversion	(315)	0	0
Net cash provided by financing activities	268,223	201,725	136,195
Net (decrease) increase in cash, cash equivalents	(46,070)	137,904	130,085
Cash, and cash equivalents and restricted cash at beginning of period	304,962	167,058	36,973
Cash, cash equivalents and restricted cash at end of period	258,892	304,962	167,058
Supplemental disclosure of cash flow information:
Issuance costs not yet paid	269	0	0
Purchase of property and equipment not yet paid	0	0	190
Non cash right of use asset	(7)	20	31
Offering costs not yet paid	$ 0	$ 495	$ 0