CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (19,361)	$ (27,141)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	85	85
Amortization of debt issuance costs	282
Stock-based compensation expense	3,379	5,035
Amortization of net contract asset/liability	(375)
Noncash lease expense	80	73
Noncash lease liability	69	82
Write-off of fixed assets	61
Issuance of common stock for cost of license agreement	1,168
Unrealized loss on foreign currency transactions	930
Changes in operating assets and liabilities:
Refund Liability	(22,163)
Net contract asset/liability	10,045
Prepaid expenses and other current assets, non-current assets, and accounts receivable	(1,072)	366
Accounts payable, accrued expenses and other long term-liabilities	(783)	5,325
Net cash used in operating activities	(27,655)	(16,175)
Cash flows from investing activities
Maturities of short-term investments		1,474
Deposit on property and equipment		(404)
Purchases of property and equipment	(86)	(28)
Net cash (used in) provided by investing activities	(86)	1,042
Cash flows from financing activities
Proceeds from exercise of stock options	1,733	244
Proceeds from notes payable, net of upfront fee	29,400
Financing costs, paid		(148)
Net cash provided by financing activities	31,133	96
Net (decrease) increase in cash and cash equivalents	3,392	(15,037)
Cash and cash equivalents-beginning of period	122,927	138,509
Cash and cash equivalents-end of period	126,319	$ 123,472
Supplemental disclosure of cash flow information
Debt issuance costs included in accrued expenses	563
Property and equipment in accrued expenses	205
Property and equipment in deposits placed in service	$ 337