CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (84,095)	$ (51,830)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	154	109
Accretion and amortization on investments, net	1,137	387
Amortization of debt issuance costs/debt discounts	627
Gain on sale of marketable securities		(19)
Gain on sales of equity investment	(1,233)	(148)
Change in fair value of equity investment, including foreign currency translation		(187)
Stock-based compensation for services by non-employees	71	54
Stock-based compensation for employees and directors	5,775	5,043
Amortization of right-of-use assets	403	647
Changes in assets and liabilities:
Current and noncurrent assets	(3,363)	(2,563)
Amount due to Janssen Biotech, Inc.		(14,269)
Current and noncurrent liabilities	7,136	8,738
Net cash used in operating activities	(73,388)	(54,038)
Cash flows from investing activities:
Purchases of property and equipment	(104)	(390)
Purchases of marketable securities	(116,482)	(220,066)
Proceeds from sale of marketable securities		7,681
Proceeds from maturities of marketable securities	178,574	128,952
Proceeds from sales of equity investment	1,594	339
Net cash provided by (used in) investing activities	63,582	(83,484)
Cash flows from financing activities:
Proceeds from issuances of common stock from equity plans	204	97
Proceeds from issuance of common stock and warrants in public offering, net of paid issuance costs		140,184
Proceeds from issuances of common stock from at market offerings, net of paid issuance costs	16,234	4,075
Proceeds from exercise of warrants	2,479	16
Proceeds from debt financing, net of paid debt issuance costs and debt discounts	10,000	24,555
Net cash provided by financing activities	28,917	168,927
Net increase in cash, cash equivalents and restricted cash	19,111	31,405
Cash, cash equivalents and restricted cash at the beginning of the period	10,288	13,914
Cash, cash equivalents and restricted cash at the end of the period	$ 29,399	$ 45,319