Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net loss	$ (83,988)	$ (103,270)
Reconciliation of net loss to net cash used in operating activities:
Stock-based compensation	23,087	12,554
Depreciation and amortization	595	305
Amortization of operating lease right-of-use assets	380	318
Net (accretion) amortization of discounts on investments	(137)	(72)
Non-cash interest expense related to the revenue interest liability	17,590	335
Change in fair value of derivative liability	732	0
Gain on sale of priority review voucher, net	(108,000)	0
Change in operating assets and liabilities:
Prepaid and other current assets	(4,009)	(1,827)
Operating lease right-of-use assets	0	(94)
Inventory	(495)	0
Other assets	(519)	954
Accounts payable, accrued expenses and other liabilities	22,655	3,683
Operating lease liabilities	(649)	(385)
Net cash used in operating activities	(132,758)	(89,075)
Investing activities
Proceeds from maturities of investments	155,600	85,900
Proceeds from paydown of investments	2,000	26,761
Purchase of investments	(198,029)	(74,562)
Purchase of property and equipment	(24)	(225)
Proceeds from sale of priority review voucher, net	108,000	0
Additions to intangible assets	(19,000)	0
Net cash provided by investing activities	48,547	37,874
Financing activities
Proceeds from issuance of common stock in public offerings, net of issuance costs	6,914	121,087
Proceeds from issuance of common stock in private placement, net of issuance costs	0	10,000
Proceeds from issuance of common stock pursuant to equity award plans	2,098	784
Proceeds from revenue interest liability, net of issuance costs	64,575	49,575
Payments on revenue interest liability	(121)	0
Payment of deferred offering costs in connection with the shelf registration and sales agreement	0	(158)
Net cash provided by financing activities	73,466	181,288
Effect of exchange rate on cash, cash equivalents and restricted cash equivalents	(1)	29
Net (decrease) increase in cash, cash equivalents and restricted cash equivalents	(10,746)	130,116
Cash, cash equivalents and restricted cash equivalents at beginning of period	142,086	11,970
Cash, cash equivalents and restricted cash equivalents at end of period	131,340	142,086
Supplemental disclosure of cash flow information:
Inventory purchases in accrued liabilities	1,018	0
Cash paid for income taxes	0	11
Operating cash flows paid for operating lease	864	576
Noncash investing and financing activities:
Revenue interest liability issuance costs included in accrued liabilities	0	229
Deferred offering costs included in accrued liabilities	0	129
Compound derivative liability related to revenue interest liability	$ 0	$ 1,264