CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 243,187,000	$ 122,661,000
Short-term investments	32,654,000	233,663,000
Accrued interest	151,000	450,000
Prepaid expenses and other current assets	5,880,000	4,543,000
Total current assets	281,872,000	361,317,000
Restricted cash	852,000
Other assets	1,206,000
Property and equipment, net	1,113,000	812,000
Operating lease right-of-use assets	31,487,000	8,692,000
Total assets	316,530,000	370,821,000
Current liabilities:
Accounts payable	133,000	963,000
Accrued expenses	15,798,000	7,530,000
Operating lease liability, current	6,297,000	3,229,000
Amount due to related party	1,945,000	572,000
Total current liabilities	24,173,000	12,294,000
Operating lease liability, long term	25,053,000	5,463,000
Total liabilities	49,226,000	17,757,000
Stockholders’ equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized at June 30, 2021 and December 31, 2020, respectively; 0 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively
Common stock, $0.0001 par value: 150,000,000 shares authorized at September 30, 2021 and December 31, 2020, respectively; 65,142,679 and 65,106,873 shares issued at September 30, 2021 and December 31, 2020, respectively; and 63,177,928 and 61,931,255 shares outstanding at September 30, 2021 and December 31, 2020, respectively	7,000	7,000
Additional paid-in capital	506,554,000	478,272,000
Accumulated other comprehensive loss	(133,000)	(112,000)
Accumulated deficit	(239,124,000)	(125,103,000)
Total stockholders’ equity	267,304,000	353,064,000
Total liabilities and stockholders’ equity	$ 316,530,000	$ 370,821,000