Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net loss	$ (91,661)	$ (114,251)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	928	912
Share-Based Payment Arrangement, Noncash Expense	16,324	20,982
In process research and development expenses	30	35
Amortization of operating lease right-of-use assets	1,363	1,284
Amortization of long-term debt discount and issuance costs	690	591
Amortization of premium (discount) on marketable securities, net of accretion of discounts	(3,036)	145
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(5,048)	(4,023)
Other assets	(90)	(174)
Operating lease liabilities	(1,463)	(1,350)
Accounts payable	716	1,204
Accrued expenses and other current liabilities	(1,051)	(2,531)
Accrued research and development expenses	(3,564)	(1,935)
Accrued compensation and benefits	(5,335)	(3,186)
Accrued interest expense	(43)	(8)
Net cash used in operating activities	(91,240)	(102,305)
Cash flows from investing activities
Research and development asset acquisitions, net of cash acquired	(30)	(35)
Purchase of marketable securities	(133,312)	(72,589)
Maturities of marketable securities	155,000	86,000
Purchase of property and equipment	0	(277)
Net cash provided by investing activities	21,658	13,099
Cash flows from financing activities
Proceeds from issuance of common stock pursuant to Employee Stock Purchase Plan	367	595
Proceeds from the exercise of stock options	0	147
Principal repayments of long-term debt	(5,807)	0
Net cash provided by (used in) financing activities	(5,440)	742
Effect of exchange rate changes on cash and cash equivalents	53	(687)
Net decrease in cash and cash equivalents	(74,969)	(89,151)
Cash, cash equivalents and restricted cash, at the beginning of the period	111,973	183,467
Cash, cash equivalents and restricted cash, at the end of the period	37,004	94,316
Supplemental disclosure of cash flow information:
Cash paid for interest	6,283	6,365
Supplemental disclosure of noncash investing and financing activities:
Operating lease right-of-use asset obtained in exchange for lease liability	0	3,029
Change in unrealized gain (loss) on marketable securities, net	$ 69	$ (413)