CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities
Net loss	$ (31,955)	$ (54,046)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	10,359	7,608
Depreciation and amortization	126	124
Amortization expense component of lease expense	695	638
Amortization of available-for-sale marketable securities, net	530	384
Realized gain on sale of available-for-sale marketable securities		(39)
Realized gain on sale of property and equipment		(70)
Changes in operating assets and liabilities:
Accounts receivable, net - related party	(8,003)
Inventory, net	(876)
Income tax receivable		810
Other receivables	(13)	252
Prepaid expenses	(3,507)	3,781
Accounts payable and accrued expenses	3,471	(3,388)
Operating lease liabilities	(855)	(780)
Net cash used in operating activities	(30,028)	(44,726)
Investing activities
Proceeds from maturities of available-for-sale marketable securities	94,250	80,470
Proceeds from redemptions of available-for-sale marketable securities, at par		8,600
Proceeds from sale of available-for-sale marketable securities	0	9,029
Purchases of available-for-sale marketable securities	(31,099)	(63,772)
Purchases of property and equipment	(43)
Proceeds from sale of property and equipment		70
Net cash provided by investing activities	63,108	34,397
Financing activities
Proceeds from the exercise of stock options	185	981
Net cash provided by financing activities	185	981
Net increase (decrease) in cash, cash equivalents and restricted cash	33,265	(9,348)
Cash, cash equivalents and restricted cash at beginning of period	13,861	32,091
Cash, cash equivalents and restricted cash at end of period	$ 47,126	$ 22,743