Condensed Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 179,879	$ 66,373
Available for sale securities	62,091	143,674
Prepaid expenses and other current assets	4,070	4,791
Income tax receivable	0	1,765
Total current assets	246,040	216,603
Property and equipment, net	2	26
Right-of-use asset, net	1,748	120
Other assets	0	5
Total assets	247,790	216,754
Current liabilities
Accrued research and development expenses	11,368	12,284
Accounts payable and accrued expenses	8,130	12,792
Lease liability	945	54
Total current liabilities	20,443	25,130
Lease liability, non-current	861	61
Total liabilities	21,304	25,191
Stockholders' equity
Preferred stock—$0.001 par value, 5,000,000 shares authorized, no shares issued or outstanding	0	0
Common stock—$0.001 par value, 200,000,000 shares authorized, 104,237,878 and 90,120,797 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	104	90
Additional paid-in capital	872,955	756,543
Accumulated deficit	(646,562)	(565,073)
Accumulated other comprehensive income	(11)	3
Total stockholders' equity	226,486	191,563
Total liabilities and stockholders' equity	$ 247,790	$ 216,754