Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities
Net loss	$ (173,614)	$ (177,720)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	1,372	1,292
Stock-based compensation expense	31,104	24,349
In process research and development expenses	50	60
Amortization of operating lease right-of-use assets	1,934	2,593
Amortization of long-term debt discount and issuance costs	893	4,983
Amortization of premium (discount) on marketable securities, net of accretion of discounts	(261)	186
Loss on disposal of property and equipment	0	84
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,151)	1,221
Other assets	451	(87)
Operating lease liabilities	(2,030)	(2,706)
Accounts payable	(2,098)	(6,808)
Accrued expenses	(1,561)	4,715
Accrued research and development expenses	4,541	3,375
Accrued compensation and benefits	(1,415)	(3,918)
Accrued interest expense	2,483	0
Net cash used in operating activities	(139,302)	(148,381)
Cash flows from investing activities
Research and development asset acquisitions, net of cash acquired	(50)	(60)
Purchase of marketable securities	(160,641)	(143,897)
Maturities of marketable securities	151,500	17,550
Purchase of property and equipment	(308)	(1,463)
Net cash used in investing activities	(9,499)	(127,870)
Cash flows from financing activities
Proceeds from issuance of common stock in a private offering, net of offering costs	119,928	0
Proceeds from issuance of common stock pursuant to Employee Stock Purchase Plan	1,215	1,315
Proceeds from the exercise of stock options	1,723	1,643
Principal repayments of long-term debt	(2,903)	0
Net cash provided by financing activities	119,963	2,958
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1,152)	211
Net decrease in cash, cash equivalents and restricted cash	(29,990)	(273,082)
Cash, cash equivalents and restricted cash, at the beginning of the period	183,467	486,620
Cash, cash equivalents and restricted cash, at the end of the period	153,477	213,538
Supplemental disclosure of cash flow information:
Cash paid for interest	7,042	7,055
Supplemental disclosure of noncash investing and financing activities:
Operating lease right-of-use asset obtained in exchange for lease liability	3,029	0
Derecognition ROU lease assets obtained in exchange for operating lease liabilities	0	1,650
Change in unrealized gain (loss) on marketable securities, net	(311)	188
Purchases of property and equipment included in accounts payable and accrued expenses and other current liabilities	$ 49	$ 0