STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (57,204)	$ (102,050)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	708	453
Stock-based compensation	5,393	5,741
Non-cash inducement warrant expense		60,751
(Increase) decrease in:
Receivables	(2,098)	(1,577)
Prepaid expenses and other current assets	8,249	(3,047)
Right of use asset	(98)
Deposits		(2)
Other noncurrent assets	(636)	9,432
Increase (decrease) in:
Accounts payable	1,713	219
Accrued expenses	3,828	810
Deferred rent		17
Lease liabilities	168	7
Net cash used in operating activities	(39,977)	(29,246)
Cash flows from investing activities:
Purchases of property and equipment	(6,012)	(184)
Net cash used in investing activities	(6,012)	(184)
Cash flows from financing activities:
Repurchase of common stock		(370)
Proceeds from exercise of stock options	43	1,020
Issuance of common stock in connection with a public offering, net	88,661	2,971
Issuance of common stock in connection with at the market offerings, net	13,015	52,499
Net cash provided by financing activities	101,719	56,120
Net increase in cash and cash equivalents, and restricted cash	55,730	26,690
Cash and cash equivalents, and restricted cash, beginning of period	79,741	61,729
Cash and cash equivalents, and restricted cash, end of period	135,471	88,419
Supplementary disclosure of cash flow information:
Compensation paid in restricted stock, gross		$ 1,000
Accounts included in accounts payable and accrued expenses related to property and equipment	$ 1,163