Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (40,665)	$ (34,843)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	128	125
Stock-based compensation	5,775	3,818
Issuance of PIK interest debt	848
Amortization of debt discount	518	364
Other	591	357
Changes in operating assets and liabilities:
Prepaid expenses and other current assets (includes the change in related party amounts of $0, and $82, respectively)	(4,384)	(965)
Accounts payable and accrued expenses (includes the change in related party amounts of $2,719, and $428, respectively)	(6,073)	(9,516)
Accrued clinical trial expenses	(1,402)	(9,129)
Accrued interest	4	0
Operating right-of-use asset and lease liabilities	22	25
Other long-term assets	(464)	(1)
Net cash used in operating activities	(45,102)	(49,765)
Cash flows from investing activities
Cash paid for property, plant and equipment	(67)	(169)
Net cash used in investing activities	(67)	(169)
Cash flows from financing activities
Proceeds from issuance of common stock from exercise of stock options		412
Net cash provided by financing activities		412
Net (decrease) in cash and cash equivalents	(45,169)	(49,522)
Cash and cash equivalents – beginning of period	183,259	287,496
Cash and cash equivalents – end of period	138,090	237,974
Supplemental disclosure of cash flow information
Interest paid	1,388	906
Supplemental disclosure of noncash investing and financing activities
Property and equipment purchases included in accounts payable and accrued liabilities	120	21
Settlement of ESPP liability in common stock	515	358
Settlement of 401(k) liability in common stock	$ 254	$ 323