CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net income (loss)	$ 8,027	$ (28,457)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation	1,802	1,643
Depreciation and amortization	901	1,144
Loss on disposal of property and equipment	47	4
Non-cash interest expense and other	3,239	6,642
Gain on extinguishment of liability related to sale of royalties	(37,182)
Changes in operating assets and liabilities:
Royalty receivable	1,164	(1,295)
Prepaid expenses and other current assets	355	436
Operating lease right-of-use asset	653	1,138
Accounts payable, accrued compensation and other liabilities	(394)	(1,915)
Long-term operating lease liability	366	(1,019)
Net cash used in operating activities	(21,022)	(21,679)
Investing Activities
Purchases of property and equipment	(29)	(713)
Net cash used in investing activities	(29)	(713)
Financing Activities
Payments of long-term debt, including fees	(12,267)	(10,550)
Repayments under liability related to sale of royalties	(6,779)	(8,627)
Proceeds from sale of royalties		35,000
Transaction costs from sale of royalties		(1,100)
Proceeds from exercise of stock options		220
Value of equity awards withheld for tax liability	(4)
Proceeds from exercises of warrants		985
Proceeds from milestones related to sale of royalties	10,000
Transaction costs for milestones related to sale of royalties	(500)
Proceeds from issuance of common stock	6,934	10,233
Net cash (used in) provided by financing activities	(2,616)	26,161
(Decrease) increase in cash, cash equivalents, and restricted cash	(23,667)	3,769
Cash, cash equivalents, and restricted cash at beginning of period	46,303	42,534
Cash, cash equivalents, and restricted cash at end of period	22,636	$ 46,303
Supplemental Cash Flow Information [Abstract]
Change in right-of-use asset and lease liability from lease remeasurement	$ 4,372