CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (37,793)	$ (21,444)
Adjustment to reconcile net loss to net cash from operating activities:
Depreciation and amortization	82	63
Amortization/Accretion on marketable securities	98
Stock-based compensation	7,617	7,447
Amortization of right of use asset	374	245
Lease liability	(361)	(173)
Changes in operating assets and liabilities:
Increase in prepaid expenses and other current assets	(518)	(41)
Decrease in accounts payable and accrued expenses	(2,498)	(2,440)
Decrease in employee related accrued expenses	(2,636)	(1,591)
Net cash used in operating activities	(35,635)	(17,934)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of marketable securities	(9,378)
Maturities of marketable securities	22,499
Purchases of property and equipment	(96)	(44)
Net cash provided by (used in) investing activities	13,025	(44)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of options into ordinary shares	293	1,532
Issuance of ordinary shares, net of issuance expenses		161,974
Issuance cost for shelf filing	(203)
Net cash provided by financing activities	90	163,506
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(22,520)	145,528
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF THE PERIOD	50,211	101,571
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF THE PERIOD	27,691	247,099
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Non-cash new lease liabilities	$ 72
Non-cash issuance cost		312
Exercise of options		$ 515