Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net Loss	$ (21,641)	$ (23,086)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash rent expense	0	92
Stock based compensation	9,240	6,991
Depreciation and amortization	38	86
Amortization of premium on available for sale investments	135	202
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	42	1,192
Other assets	165	0
Accounts payable	(1,180)	(710)
Accrued expenses and other current liabilities	(2,890)	1,623
Net cash used in operating activities	(16,091)	(13,610)
Cash flow from investing activities:
Purchase of investments	(8,957)	(11,980)
Proceeds from maturities and sales of investments	22,375	43,660
Purchase of property and equipment	(5)	(37)
Net cash provided by investing activities	13,413	31,643
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	14	441
Proceeds from issuance of common stock in connection with open market sales agreement, net of issuance costs	608	0
Net cash provided by financing activities	622	441
Effect of exchange rate changes on cash	(104)	0
Net increase (decrease) in cash and cash equivalents	(2,160)	18,474
Cash and cash equivalents at beginning of period	69,724	66,841
Cash and cash equivalents at end of period	67,564	85,315
Supplemental disclosures of non-cash information:
Right Of Use Asset And Operating Lease Liability Reduction As A Result Of Lease Modification	$ (640)	$ 0