CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (88,481)	$ (86,908)	$ (90,865)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	863	797	923
Stock-based compensation expense	20,542	15,039	14,060
Revaluation of contingent consideration	(26,900)	4,700	24,339
Loss on extinguishment of debt			752
Intangible asset impairment charge	6,629
Deferred taxes	(367)
Changes in operating assets and liabilities:
Accounts receivable	186	139	149
Prepaid expenses and other assets	(1,315)	(2,294)	(5,617)
Accounts payable	(1,473)	368	3,655
Accrued expenses	11,991	592	470
Net cash used in operating activities	(78,325)	(67,567)	(52,134)
Cash flows from investing activities:
Purchases of property and equipment	(1,309)	(605)	(308)
Purchases of marketable securities	(135,675)	(164,753)	(235,153)
Proceeds from sales and maturities of marketable securities	183,204	177,986	67,829
Net cash provided by (used in) investing activities	46,220	12,628	(167,632)
Cash flows from financing activities:
Proceeds from issuance of common stock in connection with public offerings, net of issuance costs			238,200
Proceeds from issuance of common stock under the at-the-market sales agreement, net of issuance costs	26,714	72,744
Repayment of debt			(11,483)
Payments of employee withholding taxes related to restricted stock unit award vesting	(102)	(34)	(3,124)
Proceeds from exercise of employee stock options and the issuance of stock	94	157	1,459
Net cash provided by financing activities	26,706	72,867	225,052
Net (decrease) increase in cash and cash equivalents	(5,399)	17,928	5,286
Cash and cash equivalents at beginning of period	45,277	27,349	22,063
Cash and cash equivalents at end of period	$ 39,878	45,277	27,349
Supplemental disclosure of non-cash investing and financing activities:
Additions to property and equipment included in accounts payable		$ 24	$ 143