Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net income (loss)	$ (56,731)	$ (90,935)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	153	153
Amortization of premiums and discounts on investments	173	0
Amortization of debt issuance costs	398	400
Non-cash interest expense related to the revenue interest liability	11,015	4,925
Stock-based compensation expense	4,436	5,751
Changes in assets and liabilities:
Accounts receivable	(2,182)	(4,942)
Prepaids and other assets	764	(4,866)
Deferred revenue	(2,100)	881
Inventories	(1,260)	(3,894)
Accounts payable	9,393	(21,583)
Other accrued liabilities	(3,049)	25,042
Net cash used in operating activities	(38,990)	(89,068)
Investing activities
Purchases of investments	(18,102)	0
Net cash used in investing activities	(18,102)	0
Financing activities
Proceeds from exercise of common stock options	0	2,668
Payments on revenue interest liability	(1,217)	(573)
Payment of issuance costs	(219)	(50)
Net cash (used in) provided by financing activities	(1,436)	2,045
Net decrease in cash and cash equivalents	(58,528)	(87,023)
Cash, cash equivalents and restricted cash at beginning of period	258,892	304,962
Cash, cash equivalents and restricted cash at end of period	200,364	217,939
Supplemental disclosure of cash flow information:
Debt issuance costs not yet paid	0	445
Non cash right of use asset	$ 6	$ 4