CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net loss	$ (20,971)	$ (7,826)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	37
Accretion of discounts on short-term investments	7	(148)
Stock compensation expense	1,138	1,672
Changes in operating assets and liabilities:
Subscription receivable and unbilled grants receivable	(56)	159
Accrued interest	204	(254)
Prepaid expenses and other current assets	(1,749)	(378)
Accounts payable, accrued expenses and amount due to related party	(271)	2,049
Deferred grant revenue		(158)
Net cash used in operating activities	(21,661)	(4,884)
Cash flows from investing activities
Purchase of property and equipment		(225)
Purchase of short-term investments	(26,156)	(99,344)
Maturities of short-term investments	65,000
Net cash provided by (used in) investing activities	38,844	(99,569)
Cash flows from financing activities
Proceeds from issuance of Preferred Stock		121,253
Issuance costs related to the issuance of preferred stock		(330)
Net cash provided by financing activities		120,923
Net increase in cash, cash equivalents and restricted cash	17,183	16,470
Cash, cash equivalents and restricted cash at beginning of period	61,084	24,960
Cash, cash equivalents and restricted cash at end of period	78,267	41,430
Non-cash investing and financing activities
Unrealized gain on short-term investments	$ 42	129
Right-of-use assets obtained in exchange for operating lease liability		$ 6,890