CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net loss	$ (58,794)	$ (50,964)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	178	171
Amortization of debt issuance costs	703	111
Stock-based compensation expense	7,196	8,026
Amortization of net contract asset/liability	(566)
Noncash lease expense	165	152
Noncash lease liability	133	162
Write-off of fixed assets	61
Issuance of common stock for cost of license agreement	1,169
Unrealized loss on foreign currency transactions	930
Changes in operating assets and liabilities:
Refund Liability	(22,163)
Net contract asset/liability	10,566
Prepaid expenses and other current assets, non-current assets, and accounts receivable	(2,481)	(1,017)
Accounts payable, accrued expenses and other long term-liabilities	1,576	4,229
Net cash used in operating activities	(61,327)	(39,130)
Cash flows from investing activities
Maturities of short-term investments		1,474
Deposit on property and equipment		(1,124)
Purchases of property and equipment	(421)	(172)
Net cash (used in) provided by investing activities	(421)	178
Cash flows from financing activities
Proceeds from exercise of stock options	1,747	801
Proceeds from notes payable, net of upfront fee	29,400	12,283
Financing costs, paid		(148)
Net cash provided by financing activities	31,147	12,936
Net decrease in cash and cash equivalents	(30,601)	(26,016)
Cash and cash equivalents-beginning of period	122,927	138,509
Cash and cash equivalents-end of period	92,326	112,493
Supplemental disclosure of cash flow information
Debt issuance costs included in accrued expenses	563	1,723
Property and equipment in accrued expenses	1,198	$ 27
Property and equipment in deposits placed in service	$ 1,665